I didn't know it was legal to sell babies...
Honestly, unless the paintjob was done very terribly or it's deteriorating or something, and you're planning on selling the car anyhow, just save yourself the money and sell it as-is. Someone out there might find those flames to be a major selling point (probably a young guy, 18-21). Besides, either way, you'd be throwing money away in doing so. Thing about selling cars, you almost NEVER get back anywhere near the amount of money that you put into them ... unless you're like me and deal with beaters that are $1,500 or less, and you do all of your own work...
Besides ... you just wasted over a grand on getting the exhaust redone, and now you're gonna turn around and sell it? WTF? Are you really that rich? ... or do you just like to spend money?
Not trying to be insulting, just pointing out that you're going to be taking a loss right there on that when you go to sell it. About 95% of the time, you can't throw $1,000 worth of parts/labor onto a $3,000 car and expect that someone will buy the car for $4,000.
If anything, I'd do something about those quarter-window mouldings, maybe mask things off and spray 'em or hand-paint 'em or something, but otherwise, that GT looks damned nice as it sits. Personally, as much as I love notches, I'd just keep that GT and beef it up a bit. If it's the tailpipes you don't like, you could always get a Cobra rear bumper and then throw on an LX cat-back with some stainless tails.
Side-exits ... don't do it. I've done it on Foxes, myself ... TWICE. It sucked both times. I have pics, and I think there's still a video of it up on my Myspace, but I'd strongly recommend against doing it. Why? Because...
1. Your car's ground clearance sucks, already, and any side-exit exhaust is only going to make matters worse;
2. Your direct-fit options are limited to same-side inlet/outlet Dynomax mufflers (part #37676, around $60 apiece) which is cheap but sounds like an old pickup truck, or an absurdly expensive Spintech cat-back setup. Custom-fabbing pipes to do a 180* turn after the muffs and then another 90* turn out to the sides, just to use any other brand of muffler, is not only more restrictive than stock tails, but it looks like crap and adds even more to the cost for having a shop bend up the tubing (which, as you recently found out the hard way, doesn't always turn out so great);
3. It looks weird no matter how you do it;
4. Sitting at stoplights = fumes start rolling into your interior and gag you;
5. The experience of having the exhaust noise right outside your door is cool for about 30 minutes - after that, it gets frickin' annoying as all hell, no matter what brand of muffler you use.
Again, trust me, I've done it twice and wound up hating it both times. Never doing it again.
Maybe on a bigger car like a Panther or a truck, something where I could put more distance between my ears and the exhaust outlets, but otherwise, never again.