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2004 BMW 545i vs. 2005 Cadillac STS Sport Sedan Comparison

Executive Privilege: The Standard of the World takes a midsize luxury/sport sedan crack at the Ultimate Driving Machine

Ron Sessions
Jul 14, 2004
Photographers: John Kiewicz, Brian Vance
The corporate world isn't always the best role model. Some of us are still smoldering from the idea of fat-cat Enron and WorldCom executives helping themselves to millions of dollars in stockholder and employee cash while merrily adding to their inventory of beachside mansions, flagship luxury machines, and ocean-going yachts. But America Inc. is the game a lot of us play fair and square. And when we've clawed our way to a certain level on the corporate ladder, it's only fitting that we should reward ourselves with a more fulfilling driving experience. For a lot of people and for a lot of years, the BMW 5 Series has been a benchmark of what a midsize luxury sports sedan should be.

Apparently, the planners at Cadillac feel the same way. The BMW 5 Series, along with the 7 Series, Lexus GS 430, Jaguar S-Type, Mercedes-Benz E-Class, and Audi A6 lie squarely in GM's target sights. After 20 years of wandering in the front-drive wilderness, Cadillac again has a rear-drive premium luxury sedan to wear its crest. The new 2005 STS is the heir apparent to the long-running Seville, built on the same Sigma platform that sired the edgy CTS sedan and wedgy SRX crossover wagon. It takes Cadillac's chiseled Art & Science design architecture to its most-pleasing, best-proportioned place to date. Though the car is available with the same 255-horse 3.6-liter DOHC V-6 that powers versions of the CTS and SRX, we opted to test the 320-horse 4.6-liter Northstar V-8. The STS is also offered with the all-wheel-drive system from the SRX, a feature aimed at Snowbelt--and Audi--buyers.
Compared with the smaller, more sculpted CTS, the new STS is about six inches longer and wider as well as approximately an inch taller. On paper at least, this translates to more rear-seat head- and legroom, more front and rear shoulder room, and greater trunk space for the newer Cadillac.
Our preproduction STS V-8 test car carried a base price of $47,495. Although Cadillac was still jiggering prices as this story went to press, the car's significant option load tallied thus: adaptive cruise control and head-up display ($2300), Xenon automatic headlamps ($705), 18-inch polished wheels and performance tires ($1200), performance brakes ($395), performance cooling ($150), Magnetic Ride shocks ($1850), ZF performance steering ($250), Bose surround-sound audio with six-disc DVD player, XM Satellite Radio and Bluetooth wireless communications ($3370), limited-slip diff ($300), decklid spoiler ($350), premium wood trim ($595), memory presets ($300), four-way lumbar ($295), front and rear heated seats, heated steering wheel and ventilated front seats ($1500), and extra-soft Tuscany leather seats ($1200). This resulted in an estimated as-equipped price of $63,455.
The BMW 5 Series was all-new for 2004. Though a few inches longer, wider, and taller than the previous-generation car, the new 5 shaves pounds thanks to extensive use of aluminum. Suspension arms, subframes, steering rack, brake calipers and rotor hats, the hood, front fenders, and most of the front structure forward of the windshield pillars are formed from the weight-saving metal. The 545i grabs the lovely 4.4-liter Valvetronic V-8 and ZF six-speed automatic transmission from the 7 Series flagship. That's what we call a good start.
Our 545i came with a base price of $55,695. An extensive list of options, including a premium sound system and six-disc in-dash CD changer ($1800), rear sunshade ($575), fold-down rear seat ($475), park distance control ($700), sport package including performance tires, sport seats, lowered suspension, active steering and active roll stabilization ($3300), and satellite-radio prep, ran the total to $62,620. The STS we tested was equipped with optional navigation, adaptive cruise control, head-up display, and satellite radio that, if added to the BMW, would bring its price to $68,215.
As it turns out, although both cars are in the same $63,000 price neighborhood as equipped, sport four doors, lots of luxury equipment, and four-and-a-half-liter V-8 engines with 300-plus horsepower, they have much different personalities.
BMW 545i
Announcing that BMW will no longer produce the same old sedans, the Bavarian automaker's design team applied to the new 5 Series the controversial architecture begun on the 7 Series flagship. Compared with the previous 5 Series, the new car offers a taller profile, with a raised roof and bustle-like trunk. It's a remarkable break from the past, considering how successful the previous cars were. Noted one editor, "Save for the prominent twin-kidney grille treatment, the new 5 Series looks almost Japonic." Commented another, "In profile, the 5 has substance, but almost too much; it looks thick and chunky." A third added, "those Kia Rio-like taillamps appear out of place on a $60,000 car."

Inside the new 5 Series, the extra length and height of the cabin are put to good use. "I could sit 'behind myself' with room to spare," said one editor. And the driving environment came in for praise. "This is a functional place," he continued, "the controls are first-rate and everything snaps and clicks with a precision feel." Overall, the interior-design philosophy works, save for one. Even in a revised, easier-to-use version, iDrive still confounded us. Whereas everyone agreed that the intent of cleaning up the cabin and reducing the number of control buttons was a noble one, the execution requires too many keystrokes to perform simple tasks, like changing a radio station. By forcing the driver to sift through layers of choices, it diverts his attention from what he should be concentrating on--driving a great-handling car. One writer concluded, "maybe the answer is less technogarbage people never asked for in the first place."
Photo 2/6   |   112 0408 Bmwsts 03z 2004 Bmw 545i Sedan Engine
One thing enthusiasts couldn't ask for is a more capable, better-balanced chassis. "When really chopping up a road, the 545i comes into its own," said one staffer. The weight-saving aluminum front structure helps the 5 Series achieve a near-perfect 50/50 front/rear weight balance. With run-flat tires installed as standard equipment, stiff sidewalls make for a firm, jouncy ride on less-than-perfect roads. Our test car was also equipped with a sport package that substitutes stiffer springs and shocks and lowers ride height 0.6 inch. Antisquat and antidive geometry in the suspension keeps the 5 from pitching when driven hard, and the active roll stabilization included with the sport package virtually eliminates all body roll in 80 percent of driving situations. As a result, the car feels planted and can cover big ground in a hurry.
Photo 3/6   |   Even though it doesn't look it, the new 5 Series is larger than previous one. BMW added an inch or two to its length, width, and height, and, like the STS, this mostly goes to increasing rear-seat room and luggage space (trunk will accommodate four golf bags).
One aspect of the 5's underpinnings netted its share of controversy, however: active steering. Its variable-ratio technology can change the steering from a bog-slow 20:1 to a hyper-fast 10:1. In one camp were staffers who appreciated having some extra speed at the corners of steering lock. Others bemoaned the loss of linearity. This ranged from worrying about clipping abutments in parking garages to uncertainty how the car might react in a high-speed corner. An editor explained, "The steering varies with a strange algorithm, and I never seem to be able to second-guess how much lock to dial in. The effect is particularly bad when braking from speed into a tight corner--after feeling fairly slow, the steering suddenly cuts hard, and you have to dial out lock to get back on line with your intended apex."
Variability is no problem, though, when it comes to BMW's 4.4-liter V-8. The Valvetronic engine deals with the airflow restriction of the throttle plate by eliminating it, instead controlling the amount of air ingested by the cylinders by varying valve lift electronically. Stepless variable valve timing for intake and exhaust camshafts and a fully variable intake manifold contribute to a broad, fat torque curve. Output is up, too, 35 horsepower over the previous, non-Valvetronic 4.4-liter engine. This new V-8 feels more powerful than its 325-horse rating might suggest. Part of that credit goes to the 545i's ZF six-speed automatic transmission; first gear is particularly short and gives the engine tremendous torque multiplication for launching off the line at a stoplight. There never seems to be any shortage of gear ratios for the transmission to apply to a given driving situation.

And there in lies another annoyance. One editor noted, "In brisk (but not wide-open throttle) acceleration, the engine seems to lunge from gear to gear, like a chained Rottweiler." Following a line of cars in traffic can prove difficult as well. Under semihard braking, the transmission aggressively forces downshifts, slowing the car unnaturally even after the driver has lifted off the brake pedal as the traffic begins to move again. To reduce the excessive retardation, the driver must step on the accelerator, initiating another forward lunge. Concluded one writer, "BMW needs to work on its throttle tip-in calibration and transmission phasing." Added another, "It's so hard to be smooth, especially at low speeds. Starting and stopping often come off abrupt, no matter how careful you are with the controls."
Photo 4/6   |   Our Take:BMW 545iWhat's Hot  Potent, flexible Valvetronic V-8  Balanced chassis  Great fit and finishWhat's Not  Shock & Awe styling  iDrive still too complex  Jerky driveline, steeringDon't MissActive roll control takes lean out of cornersBottom Line A quality-built, high-limit car with look-at-me styling, some flawed control interfaces, and lots of minor annoyances
Cadillac STS
If there's one appellation that sums up the new Cadillac STS, it's smooth. Compared with the Cracker Jack box square look of the CTS, the STS is clean and modern-looking without being overt. The wider stance helps the STS appear planted. "It's the best of the chiseled Caddies, an American big-car look that's tastefully done," said one editor. The well-jeweled dual-projector-beam headlamps, vertical-strip LED taillamps, and dual exhausts add interest. Noted another staffer, "the Caddy's clean flanks, generally good proportions, and surface detail remind us of the original Seville STS of 1992-1995."

A return to what works is obvious inside, too. For the STS, Cadillac has switched back to more traditional animal-type graining in the vinyl and leather coverings. It's using real wood inlays in the right places and in just the right quantity in keeping with the brand's luxury standing. GM has lagged behind just about everyone else in fit, finish, and material quality, but the STS makes up some ground here and does so in a distinctly American way. "It's a balanced, eye-pleasing combination of layout, style, function, and materials; not up to Audi standards, but generally well done and certainly better than the overwrought CTS and SRX." We'd opt to upgrade the STS's short, cheesy-feeling carpeting and molded headliner (which looks like it came out of a $20,000 car) and change the reverse-logic (you push forward for upshifts) manumatic shifter, but niggles are few.

The new STS has addressed the button proliferation question by moving most infotainment functions to a large, color touchscreen. Pushing one of eight buttons below the screen presents a menu; all the driver has to do is touch his intended selection, and he's off to the races. Though the STS comes standard with a Bose audio system, a $3300 option package upgrades the audio to 15-speaker surround sound, with DVD audio, DVD video, XM Satellite Radio, navigation, and Bluetooth wireless-phone capability. The DVD audio is one of a few concert-hall quality systems on the market, but on this Bose system you can watch DVD videos on the eight-inch VGA dash display screen provided the transmission is in Park. Need to return that DVD to the nearest Blockbuster? No problem. Just punch in that store's phone number, and the nav system will pull up the address and compute driving directions. A laminated windshield and front side glass, triple door seals, sandwich-type quiet steel in the bulkhead, and hydraulic engine mounts and suspension bushings help shut out a noisy world while you infotain yourself.
Photo 5/6   |   112 0408 Bmwsts 08z 2005 Cadillac Sts Sedan Wheel
So there's a bit of Lexus thinking in the STS; and some Nuerburgring, too. Like all Sigma-platform cars, the STS got lots of development time on the famed German race-car circuit. Inasmuch as the last rear-drive Seville was the Chevy Nova-based car of 1976-1979, Cadillac had to regain some credibility to challenge BMW and others in the segment. Like the CTS, the STS gets a stiff body structure (25 Hz), with the best rear-drive components in GM's parts bins, including a control-arm front suspension and multilink rear--mostly crafted from aluminum.
Photo 6/6   |   Rear-seat room is adequate, but isn't as good as the STS's overall size indicates.
Weight balance isn't as ideal as the BMW's, but the Caddy's ace in the hole is its optional Magnetic Ride Control. Like the Corvette and Cadillac XLR, the STS's magnetorheological shock absorbers adjust damping rates by varying the electric signal sent to magnetic particles in the shock fluid, changing its viscosity in real time according to road-surface conditions and vehicle dynamics. Each shock does this individually up to 1000 times per second. The STS is the first car to offer two selectable settings for the system--performance and touring--via the touch-screen infotainment display head. During instrumented testing, we left the shocks in the touring mode to simulate real-world driving conditions. Commented a staffer, "the ride often feels quite cushy, but it's always firm when you want it to be."
Underhood lies the latest version of GM's first volume-produced all-aluminum DOHC V-8. The 320-horse Northstar V-8 got a major overhaul in 2004; 80 percent of its parts are new. Still, with several hundred more pounds and 80 fewer horses, the new STS isn't the four-door Corvette the CTS-v is. Nor should it be. One editor offered, "Give GM credit for realizing that it cannot build a German car, but this is a nice blend of American traditionalism and up-to-date international dynamics." The Northstar V-8's throttle tip-in is crisp, never jerky. Wind it out, and it's butter-smooth, yet it doesn't have as wide a powerband as the BMW V-8 does, achieving its peak horsepower and torque higher in the rev range. Added a staffer, "rear drive is such a welcome change; now you can romp on the throttle without wrecking the nicely weighted steering."

As much as we like more gears, as opposed to less, the STS's five-speed automatic seems a better mate than the 545's six-speeder. The STS uses the same GM adaptive transmission as the BMW X5 sport/utility; it changes shift strategy based on throttle position and lateral g it reads from the standard StabiliTrak system. Said one editor, "The Caddy is always in the right gear at the right time, no hunting required, and reads my right foot perfectly when a downshift or two is needed."
One staffer summed up the STS's appeal: "Its ride is more supple than the BMW's. It doesn't handle quite as surely, but it's grippy, nicely balanced, and probably packs all the handling prowess that its owner group is ever going to ask for. Unless your commute includes 150-mph blasts on the autobahn, the STS's ride/handling balance is better than the BMW's."

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