As long as it's a motor from a 325i, all m20's are mechanically the same.
Originally Posted by downhiller
you can put in any m20 motor. but the 88-91 will be the better choice. less liters, but higher revving more hp. you can probably hit a local yard and pick up a full driveline, and computers.
The 1986 325es Delphin project LINK
Project 1988 325i sedan "Pinky" LINK