"Universal" trailer hitches tend to fit the Fiero but there was a guy on this forum a while back that made a custom hidden hitch that installed behind the fascia and located the arm insert point behind a license plate that hinged down. While a neat idea for good looks, your license plate had to be swung down for the hitch arm and ball assembly to be inserted. Not sure about that though.
Should you have occasion to be traveling a long distance and be away for a week, a trailer hitch that would allow attaching a small storage trailer behind would give more room for clothing and personal stuff. I've seen several Fieros at the shows towing motorcycle trailers.
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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "