Yes I used an engine from a 2002 CL500 but just about any engine will work. Some consideration should be given to what you want to end up with. The ML,S,CL and E class have the correct oil pan which is front sump and looks like the one on our V6. The oil pan and pick up can be changed if you find a great deal on a C or CLK engine. In Stock form The 55K has the most most power and the n/a 55 is next followed by the 500 and 43 which are about the same with the 430 having the least. If you plan forced induction in the future as I do, the 500 and 430 are best suited becuase of their 10:1 compression instead of 11:1 of te AMG motors. Some early AMG's had 10.5:1 Also if you plan forced unduction other than the farctory supercarger the an engine from a ML might be better because the engine cover would work better with plumbing the air intake.