My first car was an 89 GT convertible with manual
trans. The car I currently own is a 94 Cobra manual. Basically traded through insurance payout--amazing huh. Well, I would say that my 89 was just as quick if not quicker off the line than the cobra. (Cobra's got 240 HP vs a regular 215 HP 94-95 Mustang) so I think it's safe to say the 89 would kick the 94-95 some dirt. I'm not sure about regular and GT mustangs, but I can tell you the 94 Cobra would kill the 89 in a course race, the 89 was all over the place, terrible suspension. The 94 has really tight susp., lot more control. And it seemed like the 89 would noticeably slow down as it got warmed up where this is not the case at all for the 94. The 94 has more power in the upper RPM range too. In all honesty I would rather have the 89, just because it was a sweet car. convertible probably had something to do with it, but I just like its style better. I don't race my car on a track often so thats just not as important to me.
I'm going to make an educated guess and say the 94-95 cobra (240) should not kill a 93 Cobra (235 HP conservatively) - all things held constant. Honestly, I was a little disappointed with the 94 when I bought it. Its fast, but not what I expected a Cobra to be. Maybe my expectations were too high, but I think Ford made a pretty crappy Cobra. I know it looked like crap when I got it, Pair of Brembos, Cobra R hood and rims, and that was taken car of. As for the speed, I threw on a Zex nitrous kit and a custom cold air system. It's decent.
Well, thats my opinion.