There isn't alot out there off the shelf. You're most likely looking at a custom burn. Most Chip companies ignore the 95 and 96. 95 was the transition year from OBD1 to OBD2, so 96 was full OBD2, but then the 4T65E trans came out in 97. That left the 96 as the first fully OBD2 car, but the only year with the older trans. They don't want to waste their time on a one-shot deal.
The other problem is that the Grand Prix didn't get the L67 until 1997 when the 4T65E trans debuted, so you can't use their stuff, either.
DHP is probably your best bet (Digital Horsepower) but you typically have to take them your car, and you'll want to complete any other mods first, and be tuned to them. You may also find other sources for a custom burn.
A good source for information is www.obdii.com
I'm running the Jet Stage 2, but that'* for a 93, and even that chip is no longer available.
BTW, we have other H and W bodies, and I believe you are our 4th Riv. You're more than welcome here!