what e36 engine?? if your thinking of putting an m40 318i engine yes that would be a massive waste of time apart from the nice new fuel economy you'd get, on the other hand if you put an s52 m3 engine in this would not be a waste of time and would be extremely fast lol you need to be a little more specific about which engine, bang for buck would be an m50 325 engine, strong reliably and almost 200bhp all day long. bit of a squeeze but it can be done, e30 318is engine is also a good swap,light and revvy and packs a solid 140 bhp i think, sits nicely in an e21 bay, there are a few guys on here with various engine swaps, have a check through the owners gallery and check out some of the build threads. happy hunting.