You don't need to swap calipers, you can keep your stock calipers. I have my bolt on brackets and rotors up for sale right now. I do a lot of long trips and my spare wouldn't clear my front or rear brakes. Took me being almost stranded with a flat to decide that I should drop back down to smaller rotors in the rear and keep my spare. I don't feel like being stuck in Central FL with cows and oranges.
Plus with these brackets, it only takes 30 minutes to install the larger brakes. With the OEM brackets you have to spend an afternoon pulling the axles and smelling like gear lube.
http://www.s197forum.com/forum/showthread.php?t=120817