My '89 M3 racecar build
Motor: s50b32 from a Euro '97 M3 EVO
In order to bolt on the needed e34 m50 oilpan, you must replace the Euro oilpump with a US m50/s50 unit and an e34 oil pump pickup tube.
I removed the AC compressor and the emissions air pump. With the air pump gone, you need to block off an opening in the head right below the headers. I made a custom plate to block off this opening.
I replaced the stock crank pulley with a smaller pulley from an s54 motor (e46 m3).
Here's a size comparison between the s50b32 pulley and the s54 pulley:
Suspension and Steering:
I am running the z3 steering rack for a faster steering ratio. I also spaced the rack farther up in the subframe to reduce bumpsteer.
I also had to shorten the steering linkage in order to get it to fit. While I was doing that, I removed the rubber joint in the steering linkage.
Comparison of my modified linkage to the stock linkage: