For most of the time I had them fitted I ran them without dB killers without modification, although I actually found it pulled more smoothly lower down with them in. The Akras sounded OK without dB killers to start with, but got louder as time/Kms went by, meaning that the dB killers had to go back in to keep things polite.

I have to say that even a totally stock bike responds well to more fuel. An O2 controller and fuelling mod makes a huge difference to the usable spread of power. Well worth doing IMO anyway, regardless of what cans/filters you're running.

If you do fit a K&N, then I would certainly recommend fitting the fuelling mods, if nothing else, to make the most of the extra air.

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