Mufflers do not control smoke. IN NJ you do need to have a muffler. It can be loud since NJ DMV does not use anything to measure noise for inspection, but they do run mirrors under the cars/trucks to make sure it has cats/mufflers. Your tailpipe should come out past rear tire on a BII as far as I know. "Must exit after last opening window". Even though side windows do not open they could give you some grief about it depending on who does the inspection. NJ is not so fun for inspection. I hate living in NJ for inspection reasons ha.