Replace E30 '91 calipers with E30 M3 calipers

[asaballe]

Is it a simple job to replace the rear E30 '91 calipers with E30 M3 calipers? Or will I run into a fitting issue?

 

[E30m42cab]

I can't say for sure if it's a direct swap, but as far as I know, you will need to use M3 rotors, which means a 5 bolt patern, which means M3 5 bolt hubs (wheel bearings), M3 caliper bracket, M3 pads, and 5 bolt rims.