I agree in theory with your statement, yes there seems to be the same or even less filter area before I trimmed a little off. But other factors are at work here. In the ventilator air cleaner air has to make a tight 90 degree turn with part of the cover obstructing flow, in the Heavy Breather it has a longer curved intake runner and due to the taper in the filter air has almost a direct shot through the filter. Longer intake runners generally make more power. After installation I noticed considerably more heat coming off the motor on a few short local rides (didn't sump) as well as more intake noise. Threw a new tune on with a little more fuel, back to normal. Butt dyno says it feels a little crisper on the throttle. I did this install to see if I could get it to fit because I'm planning on doing a 124 build soon & all research I've seen points to needing a HB. Besides it looks bitchn!