Why is my car slow..?

[SlowStang2]

OK here goes. I own a 94 5.0L 5-Speed Mustang GT Convertible. I have BBK shorty equal length headers, BBK off-road h-pipe, Flowmaster American Thunder Cat Back, Mac Cold air induction w/K&N, 65mm T/B, Cobra upper and Lower intake, fuel adjustable regulator, pulleys, 9mm wires, 3.08 gears, aluminum driveshaft. With that setup i ran a 14.3@101. Not bad for 3.08s right? Well i installed 3.55s. I ran a 14.8 consistently. I had no problems in traction, launch, shifting, and the car ran as well as it did with the 3.08s. I had some1 look at it and they calibrated the computer a bit and checks for vacuum leaks...I then installed 24lb injectors and a Pro-M 77mm(calibrated FOR the injectors) and I run a lousy 14.6. CONSTANTLY. Needless to say i am pissed. All in all the car runs great. Shouldn't I be in the 13s??? And I know it isnt me, cuz after all the runs ive done (which is over 20) I would ACCIDENTLY gotten a good run by now. Come on. If there could be a problem I can't find myself or have overlooked to check, can some1 share some light on the subject? Or maybe some1 was in the same situation im in now that could be of any help, i would be most grateful. ctrlmeeee@aol.com