If you have a drop-in cone filter (stock inlet positioning), I find its ok. I also use the front end of the airbox though...

verkion

 

Passenger side vent is directly above alternator. I'm not too concerned, since it hardly rains in So-Cal and I cover that part up when I'm washing the car.

The FQ-400 vents seem to be located slightly higher up, so it isn't directly above the alternator. So I can see why its just mesh for them.