I guess you'll have to ask yourself why you buy the cars you do--what your intent is.
If you pick a cool, fast car every so many years and then trade it in for whatever strikes your fancy next, there's no reason to hang on to that Firehawk. It's five years old, the LS1 has been replaced with the more powerful LS2, and F-bodies always were an awkward marriage of huge exteriors and little teeny interiors. Logic would dictate that the state of the musclecar art has moved on.
On the other hand, if you buy cars with a view toward their potential collector status, that Firehawk could turn into an interesting historical piece one day. Do you have that kind of patience? Or budget? I had an '86 Corvette that I bought new and owned for five years, but if I'd kept it, today it would be . . . a 20-year-old, not-particularly-desirable old car. And hanging on to it would have impacted my ability to own the fun cars I've had in all the years since then (a '94 Z28, an '01 C5 and my '05 GTO).
If you have "new-car-itis" the way it appears you do, it would seem you're inclined to move from the Firehawk to something else at some point. Is now the time to do it? Tough call. Does it matter to you that your Firehawk is out of warranty? A warranty comes with a new GTO. What did Firehawks have for horsepower? 335 or thereabouts? That's more than sufficient to have lots of fun. The 400 in a GTO will feel faster to you, but not a whale of a lot.
Other than the extra horsepower, the warranty and a moderately more accommodating interior, you won't gain a heckuva lot with a GTO. If you're getting along just fine sans warranty right now, and if ponycars hold a special place in your heart, were I you I'd hold off and plunge your car dollars into the next-gen Camaro/GTO due in a year or so. If you spent your money now (and every time you buy a car you lose money that you can't get back), you might be kicking yourself in a year.
Bottom line: As much as I enjoy my GTO, I have a notion that a few years from now our 04-06 Goats are going to be viewed as kind of an odd duck, in-between car that was a Band-Aid fix for a temporary hole in GM's model lineup. I've heard some speculate that that'll make our cars all the more special, but I can't help thinking history will view these models in much the same fashion as Cadillac Cateras, Opel GTs, Merkurs and the like. What GM has in the works right now with the Zeta platform is a car that'll have legs. It'll be around a while, and it's being designed specifically to meet the needs of our market.
If I were you, I'd hang on a bit longer. You're almost there!
