I've been running my Evo IV with good success. The 415 is on the shelf right now til I finish up my LW suspension for it (hopefully 1 week). But so far the IV has been good to me. It's not as smooth as the 415 though. But that's mainly the belt issue.
No stripped front gears, but I also use the aluminium gear up front. Only thing that broke on the car was a drive cup. I posted a pic of the mod you can do to correct this. But I'll post up another one.
My car also has Pro4 front spindles that will allow me to run 28mm foams in the winter time. Plus it has bigger bearings. I'm trying to source out the rears... (Dave) hehe...
It's a good car. I just wish they would make a 3mm chassis for it. Gonna need it for carpet. Of course the TC4 will be out just in time for carpet season too haha...