I'm happy to take the minority position.
I think it looks horrible and there's NO actual chassis dyno data to support any HP/tq gains with it in a FE Cobra replica.
Never enough air? Puh-leeze. I'm sure those that have them feel "seat of the pants" gains.
And I'm betting those with them also find that by buying that belly reducing machine on TV, your belly fat will disappear in ONLY 8 days.
Get it, don't get it. I'd consider the Bernica/Mickmate dropped base unit, but for me the cost/benefit ratio is too high.