Bought a new 2010 FXDC in Oct 2010 which ran like a stock bike. Added XIED's, which lowered my MPG's, temps, and exhaust note. Drilled (3) 3/16" holes in each baffle which changed the exhaust tone a little more, but also added some slight popping and gurgling on decel. Just added Rush Slash cut slip ons w/1.75 baffles, which sound great but now there is alot of popping and farting. Removed the XIED's and the popping/gurgling is almost gone. Used new clamps on the slip ons, and I am sure there is no exhaust leak. I don't get how the popping is almost gone going from a richer AF ratio (XIED) to a leaner one (stock).

Thoughts or ideas?