i have Akrapovic full system exhaust and OEM filter but every now and then when i deaccelerate, the bike makes that popping sound. I have been told in R3 forum to go for any free flow filter and if possible ecu remapping or flash. i am not using my bike on track but just on the highways. So based on few discussions i feel that one should replace oem air filters with free flow and a full system exhaust or else just let the entire machine stock.