I used the 98+ camaro ( aka LS1 brakes ) for mine.
With just about all of the rear disk brake swaps you have to swap backing plates ( and cut off the Brake Cyl tab, drill 2 new holes.... ) but you get bigger brakes with the LS1 setup than just about any other** ( pulled from any 98+ Camaro as they all got them even the V6 cars ). IMO this makes them plentiful and the biggest brakes for the least amount of money. Replacement parts will be supported for many years due to their use on so many cars. The only drawback to any of the rear disk brake setups is that it's a PIA to set up the parking brake. I never use one so it's A-OK with me but the writeup on the turboregal site has the how-to. Oh and they fit within the stock 15" rally wheels ( in my avatar )
**- there are larger brakes to be had but it's a huge tradeoff on price to get a setup from Baer or pull something from a late model vette and try to make it work.
I bought my whole setup from a guy called firehawkjeff on fleabay. He has many sets which are USED and sells everything ( backing plates, rotors, cables, calipers, pads, flex lines ) for $200.
Do a google search on ls1 rear brakes and read up on the links to thirdgen site and turboregal site. All-in it was under 3 hours to do both sides on my car and the difference is huge.
Most would recommend that you change the MC to gain all 100% of your newfound braking power. Many ( like myself ) have not bothered as my stops are shorter, with no brake fade and no lockup.
Good luck, and do some reading.