Buy the 500. It’s simple – if you want the best performance out of your new M-Class, spend the extra and get yourself a new 2006 Mercedes-Benz ML 500. After a daylong drive, the difference between the two powertrains in terms of torque and horsepower – and the lack of a difference when it comes to fuel consumption – may justify the $10,000 premium you’ll pay. Of course, if you really want performance, wait a year and try out the M-Class ML 63 AMG, likely to be powered by a new, naturally-aspirated 6.3-liter V8 engine. Rumors indicate that the lager-and-schnitzel boys are working on that engine right now; when ready it will generate around 470 horsepower.

Ah. But enough dreaming. Mere mortals will find that the currently available models have enough power, and the seven-speed automatic transmission that comes standard on the 350 and the 500 does a fine job of handling the power output. As a “base” model, the ML 350 runs with a new 3.5-liter V6 that manages 268 horsepower at 6,000 rpm, and generates 258 lb.-ft. of torque at 2,400 rpm. The engine is fine; though on the road it feels as though it lags at times during aggressive driving, cycling a bit slowly through the upper gears and losing some of its energy in the process. Switching to the manual shift mode helps, but the 5.0-liter V8, with 302 horsepower and 339 lb.-ft of torque at 2,700 rpm, seems a better match for the ML 500’s 4,800 pounds of mass and seven-speed transmission. The 18-inch wheels, especially compared to the ML 350’s 17-inch standard wheels, improve cornering.

Still, $10,000 is a lot of cabbage for extra prowess on the road. The best thing to do is to try the ML 350 first, and if you get out with an empty feeling…call the accountant and spring for the five hundred fun blaster. Price is really the only hang up – not fuel economy, though both vehicles reportedly improved 11 percent over the 2005 model. Though the ML 500 and ML 350 are rated as super low emissions (SULEV) vehicles, EPA ratings are still atrocious: the ML 350 gets 16 mpg in the city and 20 mpg on the highway, while the ML 500 tested at 14 city / 19 hwy. A reasonable real-world average is probably three miles less for each, not much efficiency during a time when fuel economy is a growing priority among shoppers. With the difference between the V6 and the V8 at only 2 miles per gallon, price seems to be the only reason to go for the ML 350.