I installed a Two Brothers pipe about a week ago and I also installed the P1x silencer.  I have had some popping on deceleration.  I think there was a thread on the old site that had instructions on which hose, (I think it was a vacuum hose) to remove in order to stop the backfire and popping.  I have been unable to find it via the search function.

Anybody have the specific instructions or can tell me or show me via pics where the hose is would be greatly appreciated. 

-rip

There was some info on it here recently:

http://zggtr.org/index.php?topic=510.0

Thanks Gearhead.  Thanks for the quick reply.  The pics from a link in that thread were what I was hoping for.