Just thought I would share my experience with this. Had to replace my fuel pump two weeks ago and didn't want to shell out the $200 + for the full drop in assembly. Granted this would have easily made the job about a half hour long instead of two hours, but was worth the money and a lesson learned. Anyhow, after doing tons of searching and coming up empty handed when trying to find just a factory replacement pump, I stumbled across one on ebay of all places.
eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices
It's a brand new factory AC Delco fuel pump rebuild kit. Only $60!! Correct for the 98 GTP. Took some time and patience trying to fish this thing out of the FP assembly, not to mention replacing the plastic fuel lines are a PITA, but was do-able. Anyone out there that wants to save the $ and doesn't mind the extra work involved, this is great deal! Good luck!