Fiats were fun back in the day, but finicky. I'm guessing that a 30-year-old Fiat will be super finicky, but that's just a guess.

For that type of car (inexpensive true sports car), MGB is the only way to go, IMHO. It was the best of its type when new and you can get every single part for it, from the smallest screw and washer to an entire new body shell. Some people like the early Bs, but my preference is for the 1970 through 73 models.