Legion5

Why don't you get a v6 with 17k miles on it or so? This will cost 13k if you are smart about it and then after you are actually able to pay off this you can start to mod it. You'll save at least 7k off of a GT and that will easily pay for loudmouths + xpipe + xcharger + GT fog lamps + whatever else you want, etc etc

You'll be faster than a GT and you will have the option not to be hugely in debt.