Funny - I just replaced the calipers on my P30 yesterday. If you're not familiar with the key setup, which it appears you have, be prepared for a learning experience. I'm used to the "pin" style calipers. Keep track of the anti-rattle spring (it's attached to the bottom of the inside pad) and the "caliper spring". Getting the key and the caliper spring installed was a total pain in the butt for me. Ultimately I found that starting the caliper spring in slightly, and then tapping the key in behind it worked well on the left side. On the right side, both key and spring slid in no problem.
Also, I had a disturbing rattle when braking on the right side. I was happy, sort of, to learn that it's "normal" - it's the caliper rattling on the key. GM makes a bigger key to fix it. Though they might have corrected it by '93 (mine's an '84).