I did a little more research on this, and found that BMC themselves claim 98.5% efficiency on the ISO 5011 test, and go on to say:
"The panel / cylindrical air filter is commonly referred to as "replacement air filter". It is installed in the vehicle's original airbox to replace the OEM air filter. It is made of highly performing materials that allow an increased air flow combined with a more efficient filtration, guaranteeing containment of all impurities from as small as 7 microns (compared to OEM's 10 microns)."
The ISO 5011 results are not superior to most cellulose filters. The claim "from as small as 7 microns" can mean anything. It can mean it caught one 7 micron particle, and let a flock of bats fly right through.
And what OEM are we talking about here? They make filters for everything from dirtbikes to exotic cars?
Frankly, I'm a little disappointed that Porsche would install parts made by a company that makes such dubious claims. But considering that the car is supposed to be all about the racing racing racing image, I can't say I'm surprised.