I own a 05 Gt Mustang and purchased it in california. I will be moving to Md where they dont have smog laws. I dont know much about what extra that is put on the exaust out here, but I have heard that you lose horsepower. So my idea is to get this part taken off once I move back east. So, my ? is what is the part that causes the loss of horsepower and will I have to get my car tuned once removed? or anything else that may need done after the fact?

Thanks