when is it ok to rebuild an engine. i mean as far as Kilometers or miles? im curious because i may wanna rebuild my engine in the future instead of going to an M3 engine. now ive heard bad things about boring out the engine. can someone please explain why? i wanna know if it would be very bad for the engine block if i were to Force induce it (thinking Turbo) lots of random thoughts in this thread but i just wanna know what you guys think. also ive only got like 227,000 kilometers on the engine which is around 141,100 miles.