I've run C5 Corvette 18x9.5-61 rears on the rear of my '87 with 1" spacers/adapters. That means that an 18x9.5-36 would fit (61-25=36). On an '84-'87 car, you can downsize that to 17x9.5-36 without the wheel hitting the knuckle.
Why am I talking about the rear when you asked about the front?
Well for Fieros near the stock V6/stick weight distribution (~45/55), the front wheel & tire want to be 80% as wide as the rear for best handling. That means max out the rear and then go 80% of that on the front.
That results in a 7.5" wide front wheel, which is an easy fit.
[This message has been edited by Will (edited 11-20-2020).]