The fitting kit normally comprises hoses/carriers/discs and normally comes out at about 400 quid!
Normal 996 front calipers have a geometric limit of 330mm, these come in Silver or Black and have the part numbers 996.351.425 & 426, these are also available in red from the front of a 3.2 Boxster S
996Twin Turbo calipers are all red also come fitted to the GT2 and some GT3, they are 996.351.429 & 430, these have piston sizes of 36 and a rather large 44mm even though you dont expect them to work well they really do. Max disc size is 350mm
Expect to pay between 275 and 350 for calipers from either a breaker or ebay on top of the fitting kit .
The R32 setup is defo cheaper, porsche calipers being monoblock tend to run a bit cooler and are able to run 32mm wide discs which although heavier can take a good pounding on track