I've done some runs with open stock air boxes (oe boxes) but even like that the peak power isnt as good as the HRC box, or lack of it. The HRC air box isnt really a box though is it, more a means to stop large bits of crud getting in carbs.

I tend too agree with Fontyyy, a stock air box with a couple of holes in it does feel the most responsive on the road. However a good set up with the HRC air box can feel almost as good in the middle with the extra zip at the top.

A good half way house is the pod filters.
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If I have to take the carbs off once more...