I had a fiero for about a year. Put a little work into it, sold it for more than I had in it. (Which came at a good time...it was starting to piss me off)
If you go for a fiero:
84-87 had crappy suspension, and therefore handling. The 88 was much better. Kits exist to retrofit the 88 suspension to pre-88 cars. Probably worth the investment.
Engine compartment is rather cramped. Its "mid" engined, so there's just no nice way to get to it.
The "Iron Duke" 4cyl engine used in them will take a LOT of crap and keep running.
Engine tends to run cold. Radiator in front, LOOOONG hoses running from engine to radiator and back. Probably not an issue for you down in AZ, but something to think about when heading north.
It has a computer, but it doesn't really do a whole heck of a lot -- manages mixtures in the fuel injected versions (I think 84 was the only year you could get a carburated version) and a few other things to make the "buy a new car" light in the dash come on.
The headlights. Fieros are famous for having one headlight working, and the other not. Gives the car the sleepy, one-eyed look. Headlight motor runs just under $100 (give or take some, its been a couple years since I was in the market). Not too hard to replace.
The 6cyl models (especially the GT and Formula versions) are in the biggest demand. Therefore the 4cyl varieties can be had cheaper. Likewise, the 88s are in demand, so 84-87s can be had cheaper.
Manual transmissions are the way to go -- the automatics tend to be slugs. Especially when you have the AC on.
Hit the forums over at
www.fiero.nl/ for more than you ever wanted to know about fieros.