[powerbug]

You can fit the 4 pot rear calipers of a boxster to vented beetle discs as these will fit 15'' wheels.

CSP and Kerscher sell similar kits. Take a look at

http://www.csp-shop.com/cgi-bin/csho...=0&sort=0&all=

and

http://www.kerscher-tuning.de/kaefer...remsanlagen VA