I got the bike rejetted after installing the new pipes had a stage 1 a/c on already performance hasn't suffered but there's a lot of popping when decelerating and the pipes are browning as you can see on the pic. I've had people start telling it's normal and it's going to happen no matter what are they right?

 

Sounds like it's running lean to me.
Check your plugs.

 

1/4 to half turn on idle mixture screw? seemed to fix all my popping and lean tip in issues..