The rear arms are a totally different design - multilink vs. semi-trailing arms. From what I've heard the M3 front control arms & springs can swap right over from the later '96-99 M3 if you press e30 ball joints and e30 m3 control arm bushings.
Adding some e36 compact (318Ti) or Z3 rear hubs can complete the package. They both have very similar rear arms. Google "e30 5-lug swap" and you'll get all the specifics.