I have a 2008 with 700 miles.  It has a backfire at shut down that was like a shotgun blast.  I installed a HD Dyna muffler.  Now at shutdown all I get is a PFFFFFFT sound which I can live with.  The Dyna muffler fit with little fuss.  It needed a couple of bands of brass shim stock to take up the space between the new muffler and stock head pipe.  The Dyna could be fit using only one bolt at the mounting bracket, but the bolt was so close to the opening in the keyhole on the muffler, that I was concerned about it coming out.  I ground off a little chrome on the muffler bracket and brazed a bolt on the muffler and the proper spot.  Then I used the stock rubber grommets on the front mounting hole.  The HD muffler is a quality part, nice heavy shell and chrome finish that should last.  Much better than a Taiwan part.