im using home made angle iron type brackets, but as ronan says, some of the porsche monoblocs are a direct replacement. i have had a set of 996 black calipers mounted on the same brackets. the porsche calipers are bulkier than the brembos, which are bad enough for fitment. the porsche monoblocs are actually made by brembo, thus the similarities are explained.dont just assume because you have 17 inch wheels, youll not have any issues. its actually behind the spoke clearance that is the issue. ive went to a 2 piece disc setup to change disc offset, and bring the caliper further in away from the wheel.
another site is www.bira.org , although its mainly 5 stud brakes from the mk4 type cars.