Me being into performance vehicles all my adult life, I don't like buying "kits" with a fancy name brand attached to it. You are paying alot of money for that name. Take a look at Magnaflow or Hooker Aerochamber mufflers. And, look for the largest case/bodied muffler. I run dual Aerochambers on my Dakota R/T that I drag race. They flow very well. If you want to get a little deeper into the exhaust, look for a high flow performance catalytic convertor. I'll do some more research on this a little later. I'm thinking of the same "mods" for our exhaust. I just don't know if buying Banks headers for over a $1000 would be worth the expense & hassle of trying to fit them when not specifically made to fit our E series motorhomes.