The rarest of all e36 M3s was the M3R.
Many years ago one of my friends at the BMW club bought one and brought it to track days. It sounded insane. Induction noise was every bit as good as a CSL. Maybe better. It was a very quick car.
Review here that totally misses the point. It was built for the track, at which it was incredible.
https://www.whichcar.com.au/features...bmw-m3-e36-m3r
Also by the weirdest co-incidence, with a slow pace of moving houses I found this today. Signed by the man himself! Weird.