What are you looking to upgrade? Just Calipers? Would you like to upgrade just the rears? We can provide a kit designed for your needs.
I am not clear on what you are looking to accomplish? Are you only looking for a hydraulics upgrade?
The lowest cost and biggest bang for the buck, for a brake upgrade, is to remove the proportioning valve and then upgrade the rears to a 4 piston setup. Those 2 items alone will provide an unbelievable upgrade over stock!