K&N Filters 57 and 63 type, what's the difference?

[DreamofGT]

Does anyone know the difference?

I know the FIPK 57 series is 50 state legal and the AirCharger 63 Series is not, but
is there a physical/performance difference?

The K&N website seems to treat them identically.

I am just wondering what would make one 50 state legal and the other one not?

Thanks for any help/advice.

 

[sybidoc]

In the Obamanation, that would have to be 57 state legal.:lol