Saturn parts is still independent of GMSPO in many respects...if I seem to recall all their parts come from Spring Hill direct, then they are transferred to a local GMSPO PDC where they are sent out on the dedicated delivery trucks that also deliver to the "regular" GM dealerships... SAAB & Isuzu are also independent of GMSPO's direct control and they use common carriers to deliver their parts product last I'm aware.
Because I'm a Cadillac/GMC store, I can't order Saturn, SAAB, Isuzu or medium duty exclusive parts...and therefore I must procure from such stated dealerships...
IMO, if we were allowed a full spectrum on Saturn (for example) their retail & wholesale parts sales from the Saturn exclusive outlets would fall flat on the face...
As for a discount from a regular dealer...well we give our GM factory employees 15% off on parts purchases...
For years I was always relucant, as dealer employees were never offered GMS pricing (and we still don't have the parameters that the factory folks get) yet we were the ones selling and fixing their product!!!!!!!!!
I've softened my stance a little bit over the years!