yeah the 3.1 was in the GP… that would be a nice swap
IIRC they only made like 2000 of the turbo grand prix
The number of TGP’s is unknown, but I have heard there are around 3750 made. I know someone in Rochester who has a good TGP motor without the turbo, but you’d want to upgrade that anyways. I think he wants $350 for it if you are interested, I can see if he still has it.
a guy I know did a small block v8 swap into his fiero. Did it pretty cheap but it involved A TON of work.
he converted it to a front mounted engine car, and poured cememnt in the rear for weight lol… alot of fabrication was required from what I remember. Obviously it wasn’t a show stopper, but it was going to be a rocket ship… unfortunitly though, his garage burned down (with the car in it) before he could finish it 
That was just the Fiero gods getting back at him for making their perfect MR layout into some bastardized cement filled FR.