Lots of information in the forum about exhaust set-ups. Look around, do your homework and make a choice. Power, noise, torque, all the info is waiting for you to read it.
I had a 2006 Road King Classic with the Stage II 95" kit, I put on BUB 7 true duals. I like it enough, but it got too loud for my liking so I put in the quiet baffles offered by BUB, it helped a bit, but was still loud.
Currently, my 2011 FLTRU has the Jackpot 2-1-2 header with stock mufflers and it's just fine in the sound department.
2011 FLTRU Jackpot header, K&N airfilter, SERT, Corbin, Klockwerks 12", Gold Tops & Springs & JRI B shocks.