Perhaps It's just a variation in the laws from state to state, but
BBK's website (like many others) state that only non-catalytic midpipes are for "off road use" only. A long tube setup with a catalytic midpipe is
completely legal in ALL 50 states. Only the non-catalytic midpipes are illegal in most states. Perhaps you should check with the local DMV or a local inspection station to make absolutely certain. It doesn't make any sense that you can't put on long tubes with a catted H-pipe. If the law really does forbid you to add long tubes in Mass, you need to be writing John Kerry a letter.