You will NEVER find a shop willing to do that for you.. now if you want to find a way around it.. there is always the off road pipe... but if you get caught with it.. MD plates or not.. without a cat it is illegal in all 50 states. Punishable by a $5000 fine even if you correct the problem before court. If you want to do it though.. have them do you exhaust the way you want and install the cat with a flange on each end. Then have them make you a straight pipe the same length.. called and off road pipe and have them right you up a reciept for it saying "OFF ROAD PIPE". Then when you want you can remove your cat and insert the pipe yourself.. this way the company cannot be held responsible for your stupidity.