You're barely going to hear a difference with stock head pipes on a 2010 and up, the Cat absolutely muffles it.

 

I put CVO 4" on mine and i love them. It run good, nice sound and stereo friendly.

 

CFR. Nothing comes close to these slip-ons.
I had Rinehart before and once I saw and heard the CFRs, the Rinehart were gone.

http://cfrmotorcycles.com/

 

How much louder are the CVO's? I have been thinking about trying some.

 

sound of pipe is difficult to describe... I said deep sound, you here your motor when throttle or at idle but not too loud. I had Supertrapp with disc before, they are a little bit less loud but much more deep. These pipes are nice when you ride all day long on highways.

For performance, i think they are not too bad and restrictive, they are made for a 110" and i've got a 88"