***UPDATE***
I put on the 18" magnaflow today and it sounds great. Just what I was looking for. Although right when it came out of the shop it sounded almost like stock. I drove the truck for about 30 (admittedly heavy footed) and I could already tell a difference in sound. I could also smell the baffling start to burn. It has a nice low rumble and opens up when I get on it. Perfect. Also, and most importantly to me, little to no drone so far. Couldn't be happier thus far.