the evo 3 sti is a very good motor ,the evo 4(std) has the same internals as a evo 3 sti except for the rod which has a bigger piston pin on the evo4 , so both are very quick motors, now if you are looking at the std evo 3 it is a little slower( not much) but it is perfect for club racing , and if you can afford it the evo 4sti or the xxx are awsome both come std with ceramic bearings, i just ran in and used my xxx down at summernats and it is very fast