This may be a rehash for some, but I picked up (thanks Geoff @ ETR!) and installed a MBRP 4" 409SS exhaust system on my LB7 over the weekend. Below are my impressions of the MBRP product, in no particular order:

The system, downpipe, and tip were packaged very well.
The included instructions were, for the most part, spot on.
The cleanliness of the system and downpipe as received were NOT what I expected. A large amount of metal shavings and coolant residue littered the inside of most of the pieces. It was as if the pieces came of a cold-saw and were immediately thrown into a box and shipped. In short, I expected better.
Installation went smoothly, without a hitch. On my CCSB, I didn't have to cut anything, except for a little off the tail to tuck the tip behind the rear tire.
The fit-up and finish of the final assembly were good. The hangers fit well in the OEM boots and the exhaust fit nice and snug once all the clamps and hangers were tightened.
All in all, an "A-". Someone at MBRP needs to invest in some shop towels. :)
The sound - nice rumble, barely noticeable when cruising on the big road with the windows up.

My question is there any drone to this system? Drive it for awhile and let us know.

Had mine on my LLY for a month or so. Great sound, no drone, easy installation. Thanks DPP

Nope, no drone here. rumbles like a V8 should when you accelerate. Otherwise, it's pretty tame. Heck, the wife's not _too_ pi$$ed about it, and she HATED the Flowmaster 40's (sans cat) I had on my old gasser.

Haven't towed anything yet, though. I'll let you know.

I look forward to feedback after towing w/ the exhaust installed...
Any others out there w/ MBRP exhaust? Esp w/ LB7 EC/SB? I am very nervous about putting out good coin and getting "bad vibrations" from the Mrs...