I currently have a stock 323i engine wise, besides the "Johnson box" 02 sensor & catalytic converter from when it was imported to the US back in the 80s. It's currently very run down and it finally deserves a proper rebuild. I have in my garage a stock low milage 2.7 ETA bottom end with crank, rods,...

i have a 91’ 318i and i was curious how i show go about making it faster. i do not want to directly modify the engine, bc idk if it’s capable of handling anything. what are the best options when it comes to engine swaps and turbos? i know the M50 and the M52 are very common swaps, but is it worth it...