Originally Posted by BarelyAWake
Given I can hold up the stock filter sponge and actually see through the holes easily enough to read this post (yar - I just tried it lol) I daresay that any perceived "performance gain" from removing it entirely would unfortunately be either coincidence and/or a placebo effect.
Removing the cover buys a reliable 1-2mph but removing the foam after that does nothing. For some reason with the new SBP pipe my motor bogs with just the foam (pic) but runs great with foam&cover installed or no foam&cover at all.
Apparently tuned pipes need tuned intakes.