1. Fuel Filter (Purolator) - $6.96
2. 2 head gaskets - $39.76
3. Air filter (Purolator) - $11.88
4. t56 rear seal - $7.36
Total - $65.96
Your Dealer's Price: $128
But then again, some people thing that Advance Auto parts are junk. Personally, I had only one problem with a rebuilt caliper on an old car. They replaced it with no questions asked.
Sorry, I don't know the GM #'s
P.S. I like your ride. It must be a real PITA to keep those calipers clean!