Your car is supposedly the later version being a 1994

General Motors 60° V6 engine - Wikipedia, the free encyclopedia

They made 3.1 with the gen1 with iron heads, then they made gen2 a 3.1 with aluminum heads, then they made the gen3 which they called the 3100 most of the time and it also has aluminum heads. If your car is a Gen3 3100 that's a pretty good 60* with heads that flow decent. A 3400 bottom end swap is a straight swap as far as I know. The 3500 can be done with some modifications, as can the 3900.

I was(am) big into pontiac fieros so guys swap anything with a FWD bellhousing pattern.

I have an 87 with an OBD2 3800 Supercharged Series 2 swapped into it.

An OBD2 Series 2 or 3 3800 supercharged or 3800NA will probably get considerably better fuel economy than your 3.1 and have 2x the HP. I was being facetious though, I didn't really think you were doing a swap, but you did talk about manual swapping it.

Which would be possible with some J-body, fiero, and or early W-body parts.