My GTO is unmodded and I haven't raced it, but I think a few others have raced a Cobra, and there are plenty of mod-happy folks on these forums. There are SC kits for the GTO if you feel the need, but that would need a good amount of supporting mods too. SC Goats can be pretty quick...someone on these forums has one, but I can't remember who offhand
I purchased the GTO for several reasons. For one thing, my 01 Z28 was an emergency purchase (previous car was on its last legs). So, even though I was interested in a Z28/SS, I didn't get one in the config I wanted. I ended up with an A4, no T-Tops, no rear defogger (those are the 3 main things I wanted). I could have lived without the T-Tops, but I really wanted a defogger and stick. There just were not any manual Z28s for sale when I bought mine--except for ones that were quite older and/or higher mileage than what I was looking for. Or V6s.
But the biggest thing ended up being that my Z28 was getting a too-rapidly increasing set of problems. I suspect that it had gotten smashed and then repaired at shop that didn't do the best work.
I don't have any regrets about getting rid of that Z28 for the GTO. Had the Z28 been one that was working properly, with T-tops, stick, and defogger, I probably wouldn't have been in the market for a car in the first place, and therefore would have never test-driven the Goat. I'm fairly conservative with car buying, and try to only buy one as far out in time as I need to.
Both cars have pros and cons. Trying to compare the GTO now, and thinking how it would compare against a Z28 with the options I wanted, is difficult. If the GTO were a hatchback with a fold-down rear seat, I think that would be a super car, and I would have no second thoughts whatsoever. Not that I'm having second thoughts now, considering how flaky my Z28 was, but just to say.
I do think if I could compare a Z28 decked out as I'd like, with the GTO, overall I still favor the GTO. Sure, the Z28 has the hatch. But I like the GTOs slightly higher ride (Austin is very bad about having a driveway that slopes down--and meets a street edge that slopes up again), and better quality feel to everything. I feel the car will hold up for a very long time--whereas with the Z28 I was afraid at first to press the signal/cruise stick too hard as it seemed it might break off. (I used to have an 85 IROC-Z that had a broken cruise/signal stalk. When I got the 01 Z28, I was very dismayed that the stupid stalk was still the same

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