you will need
calipers part numbers 996.352.421 and 996.352.422. 312mm x 25mm discs, custom carriers, braided brake lines, vag to brembo fitment.
porsche fitment brake pads and make sure the carriers come with a fitting kit for pads, spring, pin and clip. also will need porsche pad anti rattle shims.
badger 5 do the lines at 50quid
pad shims from euro car parts at 30 quid
rear 996 pads are circa 60 quid oem or 100quid ds2500s
discs are oem 312mm
carriers come in at 125 quid from a custom maker of ukmkv1s
then whatever you get the calipers for, theres plenty for sale id say 300 tops, so 500 quid is realistic, then diy fit.
its worth getting the whole system pressure bled and changing the fluid to motul rbf 600.
great setup, more than yull ever need for road and light track useage.