I'm using their 18 inch polished, 3in inlet and dual 2.5 outlets, factory muffler-back pipes, resonators, and tips. I have had it on for 1500 miles so far, no rattle, nice mellow tone at idle and cruising, sounds awesome when u stab some meat in the throttle. Factory resonators make all the difference in keeping the drone under control when the MDS kicks in and drops to 4cyl