First I would like to give a word of advise to anyone doing this swap. If your main goal is making your E30 fast, do not do a 2.5L swap. Trust me you will be disappointed. In my opinion the smallest engine you should put in your E30 is a 2.8L M52. The simplest and probably most economical engine to swap is a 3.0L S50 engine out of a 95 M3 primarily because it already comes with most of the OBD I hardware you will need for the swap. The only problem with 95 S50 motors is that they are b