I have a 2009 and was looking to upgrade pipe and a/c. I installed a Supertrapp IDS2 with the quiet baffle so it wouldn't be too annoying w/ a K&N a/c element. I left the air box stock. I modified carb with a 45 slow jet, 2 washers under needle, drilled air hole in slide to 1/8", cut 1 and 1/2 rounds off slide spring, and turn fuel mixture screw out 2 to 2 1/2 turns. I run the Dyno at local Harley shop and a/f ratio looked to be dead on. It made 35 lbft of torque and 37 hp. The pipe and a/c was less than $400. Plus I still get over 48 mpg riding between 60 and 70 mph on highway. If you need a slow jet stop by your local harley shop and ask. 45 is the stock jet in carbuerated twin cam models. If you can't find one shoot me a message I have a ton of them!