But "easily outpower and out-handle any corvette", you are just deluding yourself there. First, on the power side, the Mustang has been at a marked disadvantage since they left the 5.0 engine in 1994. The modular 4.6 is tall (one reason the Mustang has to stay tall and chunky), heavy, and unnecessarily complex. If you want to compare power credentials and ease of modification against the LS1 family engines, you will just lose. The LS1 became the modder's engine of choice ten years ago.
As for out-handling, the Mustang has grown into a 4000 lb. heavy pig with a tall DOHC engine, a solid rear axle, and inadequate brakes while the Corvette has stayed low and more importantly 700-800 lbs lighter. Yes the Mustang can be made to perform better and handle better than stock, but so can any car, why start with something so handicapped to begin with? Mustang is fine for a certain type of car but it is not a sports car, never was, never will be. That's why it is so tall, chunky, and heavy, and most importantly why Ford still sticks a solid rear axle underneath it. It's made for drag racers more than for carving mountain roads.
I guess I'm hating on the Mustang and I really don't want to, I have a soft spot for these kinds of cars but they are what they are -- a blunt instrument that just is not a sports car and no matter how much you modify it to improve it, it just doesn't belong in discussions with a true sports car.