i tuned mine on a mustang dyno, it made 311hp then i went to a car show with a dyno jet and made 367. the dyno jet is the numbers everyone likes to see cause the give the highest reading. but what i like about the dyno jet is you tune your car based on rpm, on a mustang dyno you run your car from like 35mph to 79 mph depending what gear you run in, and it takes your power from between that speed, but if 79mph is say 7700rpms then you gotta keep making runs till you find where your mph meets your desired rpm before you can start tuning, then if you want a higher shift point then you gotta set your mph al over again, its kind of a pain. but either way just make sure you use the same dyno to tune with each time you go that way you'll know if a mod you made actually worked or not.