The air is pretty thin at 14,000 feet. But that's where we are with a group of Land Rover 4x4s, pushing the vehicles (and their drivers) to the limits. And what better place to do that than on some of the most dramatic trails surrounding the high-elevation mining towns of Telluride and Ouray in the Colorado Rocky Mountains?

Day 1: Imogene Pass
Land Rover LR4
Our first day was spent in a 2011 LR4 that's, admittedly, not much different for 2011. Most of the LR4's big changes happened last year when it got a new engine, new transmission mapping, and new suspension capabilities.

Imogene Pass is our primary destination, which, as the topo maps indicate, sits at 13,114 feet above sea level. And with the exception of a few dramatic sections where the trail is only as wide as the vehicle we're driving, the road to the mountain pass is without drama. The naturally aspirated all-aluminum V-8 produces 375 pound-feet of torque and 375 horsepower at sea level, but on our climb to Imogene Pass, these numbers drop dramatically. The typical rule of thumb is a power loss of 3 percent per 1000 feet of elevation rise. That calculates to about a 40-percent decrease in overall power. But nobody would have known it, because we were all in low range, averaging between 5 and 7 mph. We had all the torque and climbing power we needed.

It's worth noting that this new 5.0-liter V-8 (also used in the Jaguar lineup) received a few modifications that make it more Land Rover-appropriate. To begin, there is some serious waterproofing to key components like the alternator, air conditioning compressor, starter motor, and power steering pump. Additionally, the oil pan was modified and beefed up to deal with more extreme tilt angles, as well as a few expected rock hits.