the evo 4 suffers from "crankwalk"where it has way too much lateral play in the crank.i know-i bought one and found mine had it.
there is a modification for it but not sure what it is exactly.i ended up putting a different engine in it

get a 5/6.much better looking and dont have crank problem-or buy a 4 with a warranty

dont know too much about the 3