I will be buying a bunch of gaskets, a couple of new sensors, and some other items for my '95 SLE, and was online comparing prices. I was surprised that I could not find really common items like upper and lower intake manifold gaskets for the car in the GM partsdirect catalog.

It makes me think that maybe I am doing something wrong. Are you guys getting your parts availability and cost information from what they call the "Alternate catalog?" Or are you using GM parts numbers? Is there a link I am missing somewhere?

When I get parts for my vibe, i just do a direct search on part numbers (i obtained a more-or-less complete part listing with numbers off ebay).

you might also want to try http://www.partszoneonline.com. Their shipping prices are better on the small stuff...