I have a MBRP on my M8 and really like the sound of it. I've haven't noticed anything that affects the performance of sled using it so far and I've had it a year. I'm also running the speedwerx pipe with it.
I had the mbrp its sitting in my garage cause it didn't fit proper, i liked it but i must have got a bad one or something. I finally got fed up with it and bought the slp package much happier now, i heard jaws was good but loud both mbrp and jaws claim 2-3 hp gains. 100 bucks and its yours...
I have the MBRP on mine but I kinda almost with I went with the jaws, my buddy has a jaws on his 08 m1000 and it sounds sooooo gooodddd. But with my D&D y-pipe and my mbrp can my m8 doesn't sound to bad either http://www.youtube.com/watch?v=VR7OhGTkTdI
my sled with just the MBRP can, didn't get the y-pipe till after