Yeah, I used Pace for all of my GTP stuff. The guys on the phone were really good.

GMPD is a decent place, but they don't actually stock anything, they sub it out to their dealers or GM warehouses I think. So you could order the simplest little part and the only dealer stocking it might be in Alaska! So yes, it can take a while to get a part. The more obscure the part, the worse it is. For normal stocking type items it is usually not a problem. And yes, I think their shipping cost is based on a percentage of the $$ ordered and has nothing to do with size or weight.