I am a HUGE buy-don't-build advocate but, since you seem to have your heart set on this approach, take a look at a thing I penned out for another forum, at...

http://www.it2.evaluand.com/recipe.php

It talks specifically about an ITA CRX but the same logic applies to a Golf, if you are thinking of doing a gradual kind of build up.

It is probably pretty presumptious to think that I have the answers but please believe me when I say that I have personally dorked up the race car process pretty much every way possible. I just hate to see others suffer.

Kirk