I had the T409 SISO. It sounded like no other I loved it. I had all kinds of people asking what I was running. The sound is very deep very unique. I had it for over a year and couldn't tolerate the 1800rpm drone any more. I tried moving the tip as far out as possible no change. I did u bolt a 3 foot 3/4 inch steel bar to the mid pipe, that made the drone a bit quieter. I ended up getting a 18 inch SIDO maggie. Well it's no mbrp but the sound isn't to far behind. The 1800rpm drone is very tolerable now. If I was single with no kids in the back seat I'd get the mbrp for sure.