Wow, there sure is a lot to learn about it I guess. I was always curious about the whole process. I think you are doing the right thing with the CPO..
LA, I wish I was there to buy your Z4, Id put 2 coats of Z5 on it, stick a "Vanillaroma" under the seat, and put a 2k mark-up on it...GOTCHA! People are suckers for a pretty car..
Make some $$$ on it!