well the 4,5 and 6 are virtually the same and any differences can be updated to either model, hence a cheap evo 4 making a good project. Obviously the 6 is better as it is a later evolution of the car but everything from the 6 will fit in an evo 4 or 5 . Then i think it is the same with the 7,8 and 9 but am not sure. The early evos chasis aint as strong as the later ones but they are still just as good. Hope that helps a bit
I currently have an evo and series 2, the evo wins hands down in everything and i would recommend one to all. HOWEVER IT IS NOT AS FUN AS DRIVING THE RS . There is just something about being behind the wheel of an rs that i love and i am sure we all do, its like no other (when they run right )