http://www.bira.org/ are a well known company who supply brackets, The Calipers will fit some 17`s but to be safe get 18`s.
Evoms may also have them- pic below is evom`s 996 brackets.
Not certain but pretty sure the servo should be ok, and the disk if are the usual 320mm ones should bolt on.
Ive been reading up on B5 though so look on ECStuning`s site as well as AW and AZ /ubbthreads/images/graemlins/beerchug.gif