I have 17's on the 86 with a 35mm offset but I'm running 40 and 45 series tires. I also have a set of 17's that were on an 86 GT and on the Lil Duke Coupe. I don't know what the offset is nor what size tires I have on them, but there were no issues. Looks like the guy was already running them on a Fiero. I'd ask him why he is removing them so quickly. I'm guessing he has some kind of clearance issues.