For my nickel, it was the '82 Mustang GT that single handedly restarted the Musclecar market in this country.
Ford had upped the ante, and Chevy responded with the '83 Z28 HO, Buick started getting very serious about its turbo V6 program, then came the Monte SS. Before you knew it, GNs were pumping out obscene (for the times) power, there were 5.7 Camaro's, Aero Montes and Gran Prix 2+2's, 442's and Hurst/Olds again, and Turbo Trans Ams
It was a fun time to be a car lover again, and the aftermarket was again awash with performance parts for people who wanted to tweak their new "hot rods".
None of this happens without the '82 Mustang GT sparking the horsepower wars again.
