have a look here at this forum
http://www.germanlook.com/Forums/forumdisplay.php?f=10
Its a forum for VW beatles who tend to upgrade to porsche brakes quite often. My friend is in the process of upgrading the brakes on his beatle with 996 (i think) brakes and the cost is becoming ridiculous. There should be some useful info on problems you may encounter on the forum.