Alright, I took the TPS from my Impala and placed it on my Grand Prix. I had NO SES light on the Grand Prix before I did this. I put the Impala TPS on the GP, and disconnected the negative battery connection to clear any codes. After my second restart, SES light was triggerred, P0122 - Bad TPS code. I have not had the same hesitation problems in my Impala, and of course there has never been a SES light on the Impala.
So my original plan of moving Impala TPS to Grand Prix is a no go. I evidently have two bad TPSes! But since there has been no trouble on the Impala , I'm going to put its TPS back in place, and buy a new one just for the Grand Prix.
It's entirely possible that the Impala TPS has been bad for a while, but at highway cruising speeds, I'm under 2000 RPM, and when I do punch it, the supercharger may cover any hesitation I may have. I'll have to buy a new TPS for the Impala eventually, but I want to minimize the wallet impact.