I ordered 5" exhaust from Rollin' Smoke Diesel on Thursday....it showed up today! All I can say wow, they are really on top of things!
I should have a chance to install it sometime in the next week or so, I'll post how it fits.
Just thought I would let everyone know how impressed I am with RSD's shipping.

 

yeah i got mine from RSD also and have to say they are great at customer service and quick on shipping. had a few questions and the guy that i spoke with took time to answer all of my questions and really helped me out. from now on all my stuff gets ordered from them

 

Install for the 5" exhaust was easy...like everyone says, getting the old out is harder. It's a little loud above 2K rpm's...I'm going to wait and see if quiets down a bit after some soot gets built up.
I might be going the nelson/donaldson route. I pull a 20K lb. trailer around during the construction season.