Man, you bought somebody else's problems...I feel bad for you, but that inspection is what you should've done BEFORE you bought it. Did you buy it from a dealership? Because if you did, you could probably cite the lack of a catalytic convertor as reason to return the car/get a refund. If you bought it from a private seller...Well, you may be out of luck. I would trust Cobb, they typically know their ****, but I guess I can't speak for their shop.