Thanks for the great info, I will definately save this and refer to it when researching this a lot further. regarding spending the money on driving, I am way ahead of ya, I definately plan on hitting the BMW track in NC and doing a lot of other courses offered through the comapny I work for.
I just dont have the mechanical or technical knowledge not to mention the experience with the Z4 M Coupe specifically. I know there are a lot of people here who have tried and tested many many versions of mods so I figured it to be the best place to ask.
Thanks again, I appreciate all the help.