How loud is it? My buddy's 4" MBRP on his LB7 is about as loud as I can go. I know the LLY turbo quiets things down a bit though. Its the resonation that bothers me more than the volume. Also, how is the fitment...I havent really seen much posted about that. Thanks.

search results.. page one has threads about sound, page two(linked below) has fitment posts.

http://dieselplace.com/forum/search.php?searchid=305599&pp=25&page=2

I knew I'd get the "search" routine, LOL...I guess I deserve it as I give it to others on another board I moderate...I was looking for a few more replies from some different people. Results seem to be all over the board...pardon the pun. Some think a straight pipe coming in the cab is quiet. Some complain about the stock exhaust having a drone. But thanks for the help.

Well if you want my suggestion and if quiet is what you want I would go with Banks monster exhaust. I just installed mine and its just as loud as stock it just has a deeper throatier rumble to it. Under normal highway driving you cant barely hear it. Plus you can find the cat back system for about the same price if not cheaper than the MBRP, I did.

getting the "search" routine isn't that bad. At least I posted some results for you. ;-)
From what I have read about the 5" it is much louder, but has no improvements over a 4" system unless you are over 500hp.
If you want the sound then that is one to get. As far as fitment, most reply saying around the spare tire is hard. Its all in those results I posted.
good luck

Think I read every one of those results...I mainly wanted a 5"er because its something different than what everyone else around me has. I'd love to have the Kennedy 4-5"...I know thats quiet and fits, but I don't feel like spending 650 for it, when I'm still picking out tires. Could always put a different muffler in there to tame it down. That summit one looks like an unpainted cherry bomb...

To get it louder it dont matter, just get rid of unneeded restriction (cat, muffler, bends in pipe) The larger the pipe the quieter it will be the smaller the more restriction...I would go with a 5" thats what I run. I have seen 4" and 8"...The 8" was extremly quiet!
I went with 5" becuase most people go with the 4" when the stock size is 3"?!?...didnt make sence until I found 1" will make it flow 98% better..So I guess 5" makes over a 100% flow increase compared to the stock flow ratings. And I have Dual so there is pretty much ZERO restriction, no DRONE and is loud enough to hear me from about 3-4 miles away.

I have the summit 4" exhaust and that dam this loud!...especially at WOT. If you don't want loud I would not reccomend the summit exhaust

Go loud and put the 5"

I got the five inch Summit exhaust with the muffler. I think it sounds good. Not too loud until you get on it. The only way to describe it is that it SCREAMS! I have a turndown on mine so it echos a little off the ground. Fitment around the spare, shock, springs, and mud flaps is tricky. If you don't need the spare - ditch it.

Well if you want my suggestion and if quiet is what you want I would go with Banks monster exhaust. I just installed mine and its just as loud as stock it just has a deeper throatier rumble to it. Under normal highway driving you cant barely hear it. Plus you can find the cat back system for about the same price if not cheaper than the MBRP, I did.
:exactly: i just had a the same install on my 05 gmc with the cat gone and it is very quiet to quiet for my liken, truck does run a lot better though

I have the Jeg's 4 inch turbo back, about the same as the Summit and all I can say it sounds good up in the higher RPMs. You get some noise when cruising at certain speeds inside, not real bad, but its there. All I can say, people know its me and they say its got its own tone.