Providing you do the work yourself 2G's would give you the LT's with HF cats AND the Driveshaft. That's what I'd go for if I had the cash you speak of.
From the signature I can tell that you're a track guy so I really suggest you invest in a Watts Linkage.
If I were in your spot (i.e. not having a WL already) I'd get one which is about 600 bucks, dump another 600 in an SLP Modular X-pipe with HF Cats (which can be used on long tubes at a later time), and another 600 in the driveshaft which leaves me 200 bucks to play with for other stuff like maybe an HID conversion or something cheap like that.
You got a Shelby GT which is a great starting point already having a Hurst Shifter and the FRP Suspension.
I would keep the wheels you have and get an Aluminum DS, Steeda UD Pullies, Hiflow Intake "elbow" if you don't already have one, UCA and LCAs if you don't have them, and last but not least the Long tubes and HF cats with a custom tune!
I wouldn't waste it on LT's unless you want them for sound.
With that amount of money you can do gears, driveshaft, UD pullies, and a custom dyno tune and still have enough left to throw in a CAI. But I'm not sure if the SGT needs one.