You'd be best off looking on eBay bud consider also the R8 brakes and Porsche all of them are made by Brembo, the kit that I have is the front calipers from the 2.5/2.7 Porsche boxster with adaptors purchased from a guy on the forums Dave Brown they fit to your existing 312mm disks but a 2 piece alternative can be bought from I think AP.
Darren