I have reason to believe the computer in my car, well lets just say has big issues, what is required to change it out, is it as easy and unbolting the old one and putting in the replacement, after I disconnect the power?

 

Yup, just unbolt the harness the PCM sits in, pull it out (A tight squeeze) and put the new PCM in it, make sure you get the same year PCM though, so u don't run into any problems.

 

I got one coming that was on an automatic, I understand there is a chip I can just switch out from my m5?