Like djl said it's the filter that matters. Just about any air cleaner housing is going to flow more air than any twin cam build can use with the right filter inside of it. K&N and Green are the top performing filters as far as I know.
That said, I stay away from SE anything. over priced and generally EPA compliant which is NOT conducive to performance.

 

How much extra power do you think one air filter set up over another is gonna give you?

Will you notice it by the seat of your pants?

Or are you more interested in what the dyno may tell you?

Get a filter that'll keep air-borne crap out of your engine.

Get a K&N and maintain it.

 

Most cases Any seat of pants difference is just wishful thinking and or excitement of a new toy.

Even factory AC flow more air than most can use. Some AC do sound cool. when rolling on hard.
Kind of like when we flipped the cover upside down on the car to get more air flow.

 

Just don`t add one of these hideous abortions.

 

But, but, it looks so cool; makes my bike look really fast.

 

Only when you add a skull medallion..

 

Pick the one you like to look at best. You’re not noticing the gain an AC is going to give no matter what. The Ventilator breathes just fine. I have one on my stage 1 and the same on my Stage 2. When talking to a fuel Moto I asked if I needed a better AC for my Stage 2. They said no. The Ventilator was more than good enough.

Beware of the Kool Aid crowd. If you’re not going big bore most everything other than stock is fine. And your *** isn’t noticing 3hp.

 

I think once people understand how many CFM's their stock heads actually flow they will realize most AC's are fine.

 

Depends very much on the engine configuration; more specifically what the engine wants/needs. Stock engines are not too picky, however as engine output increases the ceiling on the peripherals (exhaust, air cleaner, etc.) increases as well.
See the dyno chart below; a back to back test of our BMF element for the H-D Ventilator air cleaner we did 7 minutes apart on a 124" big bore M8 engine. The standard filter is simply too small for this application, the larger element on the same air cleaner picked up +6 horsepower +6 torque. While this would not be the same on a stock engine this example shows the importance as power levels increase.

 

Found this out on the dyno myself. Hit a brick wall at 120/120 with the cheap chinese filter in an expensive Trask AC. Picked up an instant 5/4 and went on to get a little more after trashing that filter.