Best of all, the factory muffler is huge and only bolted in. Your truck gets lighter just by losing that fat, chambered, too quiet beast.
Because the OEM is bolted in, you can buy a prefab replacement and DIY it. I have the Mufflex which uses a Magnaflow 24" single in, dual out and I added 5" tips for a little GRAVITAS (changed note deeper).
Why pre-fab kit? You'll need make-up pipe since nothing is a YUGE as the factory boat-anchor. A muffler shop may use aluminized steel because it's cheap and you're not standing there under the truck with them, or try to sell you an entire Cat-back that you DO NOT REALLY NEED.
Mufflex takes a 14", 18" or 24" Magnaflow and welds it with the same stainless pipe as the factory and includes the hangers and clamps. As mentioned in posts above, Carven has similar kits and other's do too.
I like the 24" because the exhaust notes says "Hey I got a Hemi!" not, "Hey I'm begging for attention and don't care if you or your kids are trying to sleep--its all about me!" Some exaggeration there, but there is also the issue of freeway drone, especially when MDS cuts out half the cylinders on the freeway. I don't get anything annoying with the 24", and I've heard much gnashing of terrible teeth and roaring of terrible roars and rolling of terrible eyes from folks that chose shorter mufflers.
To be fair, I've also heard from folks who love their short mufflers or even muffler deletes--but I guess their Po-po don't carry decibel meters in the trunk the way my local five-oh does.
So listen to a bunch of videos on YouTube, ignore the advice/opinion of everyone including me, and buy what you like, since you have to live with it, and the rest of us do not.
