2006 Cadillac XLR-V Chassis, Engine, & Powertrain Review

The XLR's chassis architecture is unchanged for v duty, but the tuneables received a makeover. Suspension bushings are stiffer, the front anti-roll bar is beefier, and the rearend gets an anti-roll bar, which the base XLR does not. The magnetorheological shock-absorber system is recalibrated for firmer damping. The biggest (and besides the engine, maybe best) part is a new six-speed automatic transmission. Mounted at the rear to enhance the car's balance and weight distribution, this is the tranny GM has needed, not for years, but for decades. It offers a standard-drive mode, sport-drive mode (quicker shifts at higher rpm), and a shift-it-yourself gate. Select either of the last two, and the shocks automatically adjust to sport mode, rightfully assessing that, if you want to shift more aggressively, you'll want the better handling to go with it.

GM asked us not to do a back-to-back comparo between this preproduction test unit and an SL55 AMG. But just looking at a few numbers reveals that they're playing in the same sandbox.

The SL's 493-horsepower monster motor gives it a 0.4-second edge in the quarter, no surprise given its 50-horse advantage. But the Caddy's lighter curb weight--estimated at around 400 pounds--is easier to launch from rest, keeping it close in the 0-to-60 run. On the fly, the Mercedes's rear end stays planted a smidge better than the XLR-v's, hence the slight advantage in our slalom test.

While every last tenth and mile per hour is important to a performance model, so is its on-road reality. The XLR-v is a blast to drive, particularly through long fast sweepers. The front end bites and turns in confidently. We expected quicker steering and would always take a smidge more feel, but there's a solid connection between steering wheel, front end, and tarmac. The Caddy has all the grip most of its drivers will ask of it, and its ride handling/balance is spot on. Bumps and road rash are soaked up with aplomb, yet body motions are well controlled. Brake feel and modulation also are up to snuff. The structure is tight and rattle free, contributing to the XLR-v's overall solidity and sophistication.

The powertrain is superb from stem to stern. Going fast requires little effort; just stomp the pedal, and the engine management and traction/stability systems get the power to the ground. You'll know the engine packs a blower, but the traditional supercharger whine is never overwhelming. At modest throttle inputs, the exhaust emits a polished blare; mash it, and the muffler baffles open up for a deep rumble. The engine delivers its power and torque over a wide rpm range and exhibits no bad habits. It just freakin' goes.