Going custom is not much more, that is depending on what you do. I was gonna go with a single 3" with sebring muffler and high flow cats for 1100 installed. Thinking about going with a single 2.75" or dual 2.25" with test pipes now.

 

If you want some sound clips of the Stillen Gen II let me know and I'll make some for you. I just installed mine a few weeks ago and I love it.