The Fox body Mustangs are crap, and that's coming from a Mustang fan. Bone stock, the live rear axle sucked the life outta the handling, the twist in the chassis nailed the coffin, and 225 bhp sealed the deal.
Might as well ask for an Escort (US not UK) while we're at it.
That's not even begining to mention the misguided tuning options that has always befuttled Mustangs in all GT games. Really, no turbos? No supercharger? Why not? There's no reason for that!