My bike 2010 Z, OTR blue foam filter kit, MTC titanium single can with home made baffle. Bike ran fine no surging pulled from low down ok. Fitted the 02 controller well ****** me it's like riding a different bike, I can change up earlier and potter in a higher gear. This did lead to a few problems at first mainly stalling the bike as I was in 2nd gear instead of 1st.
This made me want a Kev mod to improve top end and dash mount it had a look at Kev's but to big to fit behind plastic panel so made one (sorry Kev).
Now the interesting bit with the Kev mod is you can see it working. Bike in neutral get it warmed up hold at 3k rpm then play with your Knob, turn slowly up there will come a point when the rev's will suddenly rise mines about 3 o'clock turn back rev's drop.