i bought it used off a buddy, i was running a ffp box before but was restricting my exhaust with the 1 1/2". i cut the T off right away to make it fit better and allow me to change the angle that the box sits in the hull. i was getting a big kink in the silicone hose that comes off the pipe to the box. it is lighter, holds less water, and make a great deal of noise, if makes more power? i don't know, but this new setup in combo with the 2 1/2" after the box is working very well with my setup.