If you're going to do the Grand Am upgrade on the front, consider doing the Seville upgrade on the back. This consists of 85 Seville rear calipers, the same Grand Am front rotors as used in the front upgrade, and brackets made by DPWood on Pennock's for attaching the Seville calipers to the rear caliper positions on your car. This gives you better rear brakes, including e-brakes.
I had done this upgrade on my 86 SE, which my younger brother now has, and did a write-up on Pennock's about how I did it.