You have to replace the wiring harness...U have to replace the computer...And then tranny...Altho with tranny problems...i assume you would be doing that aswell. This would be an AMAZING swap. Because u could leave ur rear diff. in the car. And with a much bigger engine, your low end power would be great...And with a 6th gear from a 3.2L engine...You wouldnt loose high top speeds. If u have the money(Its gonna be like 8 grand or more)then do it...Otherwise...sell ur car, get an M3