twobjshelbys
GT Owner
I have the GT Guys pulley and tune on my white car with 37k miles. I have to load the stock tune when I get it inspected every year with the OBD-2 test they do here in TX. Minor inconvenience.
I have the GT guys tune and didn't have to do anything to pass Colorado test. They hook to OBD-2 and also visual inspect for cats. Then they do the sniff test. No dyno run because they said it would tear it up (too much HP for their setup). They don't measure HP (wish you could get it!) but use the dyno to get the car up to driving speeds during the test cycle.