Thats something you will have to ask your local BMV. Emissions regulations vary from state to state, and in Ohio even county to county. Like the other person said most states exempt people who have Historical tags from emmissions tests, Many states exept cars that are older than a certain year. Just call your local BMV and ask them if you have to have an emmissions test on your car to register it. In many states such as California it is illegal to tamper with the emmissions systems and you will be hard pressed to find a mechanic who is willing to take it off and run a straight pipe. Other states don't care. I guess it would be interresting maybe to dedicate a topic to Smog laws in each state so I will pose a new question in the General Topics forum.