Have a look at this tech article that retrofits 944 brakes to a 924, it applies to the Superbug because the early 924 used the Superbug brakes (with a 4x108 mm bolt pattern).

Take all the information is in this article but use the Kerscher conversion parts (ball joint and e-brake adapter) and you're ready for the brake upgrade.

http://924.org/techsection/9brakes.htm#3 - Brake Conversion