At 5,000 miles I installed the Mufflex 24" kit on my 2010 1500 Big Horn. Installation was a snap. 1 hour. Did not have to jack up the truck. I am approaching 10,000 miles.
I like the extra noise and the tone except for when under load between 1500 and 2000 rpm there is a heck of drone, tow/haul mode or not.
When towing thru the hills between Phoenix and Holbrook on a recent trip, I had to drive in 4th in order to keep up the rpm's and get rid of that irritating drone. The rear facing exhausts also bellow off the trailer which doesn't help.
The MDS sound isn't as irritating to me as the drone. I've actually thought I might have to go back to the stock muffler.