I just replaced my stock 2-into-1 exhaust w/ Screaming Eagle night stick muffler for a new set of Freedom Performance's Racing Duals true dual exhaust system w/ 4" mufflers. The install went about as expected - but be forewarned, the system does NOT include instructions. You have to contact the manufacturer for them and they'll email them to you. As well, the instructions contain no pics, so you have to kind of figure out how their brackets go on and where they go. Lastly, going from a 2-into-1 to true duals requires the purchase of a saddlebag bracket to hold the #new# left muffler. You can get them from any HD dealership for a few bucks. Once done however, the system looks and sounds great. I got an immdieate huge bump in power and response. Stock, the bike was very sluggish, but now, the response is much more quick and the top-end power is quite noticable. I am very happy w/ the result.