There is also a tech article on the main site. I will say that I looked into the 3.4 swap, and opted to do a v-8 swap instead. Basicly, you have to pull your 3.1, disassemble the top end and reassemble on the 3.4 (which you've already stripped down to the shortblock). Then you put it back in. After a few days, weeks, months, you'll trash your tranny b/c of the 3.4's increased torque. So, you guessed it, you have to pull the tranny and rebuild it. So I don't think the "cost benefits" of a 3.4 swap are that much better than a v-8 swap. Maybe it's just me, but if something breaks and I have to take it out, I'd rather put something in its place that's better, not the same.
But if you want to do it, contact Karl (KED85), he's the one that wrote the tech article. Fiero websites also have a lot of info on the 3.4 swap. | 
