Mazda debuted its newest high-performance vehicle at Los Angeles, touting the MazdaSpeed6 as the most powerful and best-handling sedan ever sold by Mazda. (Semantics: The title for most exciting four-door would go to the RX-8.) When the car goes on sale this summer, it will be powered by a 2.3-liter/270-horsepower turbocharged direct-injection engine that benefits from an all-new six-speed manual transmission and new Active Torque-Split all-wheel-drive system to effectively transfer that power to the pavement. The base-level MazdaSpeed6 (Sport version) will retail for $27,995; the Grand Touring package, which includes leather seats, eight-way power driver's seat, heated front seats and mirrors, and keyless entry and start will sticker at $29,990. Both versions feature a long list of niceties, including four-wheel anti-lock brakes, 18-inch aluminum wheels, sport-type front seats, Bose audio system with in-dash six-disc CD changer, and alloy pedals. Pearl paint, power moonroof, and DVD navigation are the only factory options. And, like every Mazda, the 2006 MazdaSpeed6 comes with a four-year roadside assistance program.