Can you believe this!  (Keep in mind, I didn't want to touch the performance of the bike, because it runs just fine for me).  I have an 09 FLHX with Performance Machine Torque wheels, matching rotors, and Metzler tires.  I put the Rinhart (Slip on) pipes on to get a little louder/deeper sound.  I wanted to add the Performance Machine Statge 1 air cleaner, with the matching "Torque" insert, to complete the theme with the wheels.  (Just for vanity).  I wanted the look, but didn't want to put a fuel pack or race tuner in because of all the problems I hear people encounter once they do this upgrade. (Dyno and so on)  Many mechanics stated I will have to do something because the bike will run too lean.  The dealership I bought the bike at stated I wouldn't have to do anything.  They've been adding pipes and stage 1 air cleaners since 2008, and the bikes run just fine. No back firing, spitting, farting, nothing.  So I added the pipes and Stage 1 air cleaner and low and behold, the bike runs fine.  The O2 sensors adjusted the mixture just fine.  The bike doesn't run any hotter and no problems at all.  Just an FYI to anyone who wants to get a nice sound and look without installing any maping system, fuel pack or race tuner.  You don't need it! I probably saved over $1,000 (The cost of a race tuner and a dyno run).