So, I took the car down the 1/4 mile today. Even with a different ECU, a bigger VAM, deleted cat and a bit more boost it only managed a 17.94 @ only like 72. This all fairly well confirms what I already knew. Car is lean all the way down the track. Going to order an adjustable fuel pressure regulator here in about 5 minutes, that should solve that.
Meanwhile after driving the car for a couple of days now I'm not sure the brakes are warped, rather the parts Perc pointed out are probably shot. I'll have to get a Mustang out of the garage, it's not mine by the way, and confirm next week after a trip to the Carolinas.