Are you wanting the car to race or for street? Or just to own a badass mustang? If it's more to race than anything, I'd suggest you just get a base, regardless of gears, then for a couple hundred bucks get some 410 gears and put in it, then follow up with exhaust, CAI, and tune with the money you'd save from not buying a premium. But if you want more out of the car you're gonna want to get the premium. The brembo brake package makes a world of difference, and it's not just the brakes, the suspension is a little different too. Just try to find one that's not decked out with the glass roof, appearance packages, etc. Also, keep in mind that you are the customer. You don't HAVE to buy from that guy, don't be afraid to walk out. Patience and perseverance will get you the deal you want. Also, I got rediculous credit. That helped too.
I'll hit the drag strip, maybe some autox. Just for fun, more than anything just a nice one to drive, probably tell myself not to do any mods for a few years. I didnt like the seats, gauge cluster, and radio in the base