How fast do you want it to go? The ML320 isn't a high performance vehicle. The 98's and 99's go 0-60 in a hair under 9 seconds. The later models do it in about 10. The first problem in making more horsepower is $$$. At $150/hp it can set you back quite a bit if you want any kind of tangible increase which translates to better accelaration on the road. For a few dollars more you can get an ML430. Second problem is the drivetrain. The ML320's transmission cannot take more torque. The M112 engine puts out 233lb/ft of torque. The transmission maximum torque input is only 231lb/ft! The engine's max torque already exceeds the max torque input of the W 5A 300 transmission. Any more and you will find yourself in a big $$$$$$$ hole!

You want speed, get together 6k and buy yourself a Porsche 944

Kuan