quick question , 1989 318is? does this exist or is it 90 and 91 only

does that meen that the flywheel off a 325 flywheel might fit?

i have my is a while now and am looking to get the most out of it ,any suggestions for what i could do performence wise firstly the clutch has to be replaced

i recently bought a 318is and was just wondering what i could do for more power . any sugestions on tuning or extra stuff to giv me more power?