I'm running a 2012 S3R. I bought it stock and like you wanted to change it up. I found that all the aftermarket mufflers were really high priced for what you get, so I went a different route. I went to the junkyard!! I researched the different mufflers and measured the inlet and outlet sizes. The one i settled on is from a 2009/2010 GSXR 750 titanium stock muffler. It bolts right on, reduces the weight and lowers the C of G. I made a new hanger for it and was all set. I considered changing the tune on Tunecu, but did not find that I needed to.