Stock Air Intake

[2000BMW323i]

on my bmw there is like a plastic vent that goes from the front grille to the air box, wouldnt that be better than if you remove that and put those K&N cone filters in and remove the factory air box?

[Furious]

depends on what you consider better, performance wise yes cone filtered intakes with heatsheids breath much better than stock boxes, but you may not feel a huge gain , possibly might actually feel less power on the bottom end.

[peterkulesza]

i agree. to add:

little two plastic vents help (they deliver colder outside air, versus hot under the hood air.). there are two, the one you mentioned, and another sandwiched in the middle of the headlight unit.

my bigass cone filter (afe, bought at bavauto), replaces the stock airbox, and kooks up the plastic vents. heatshield protects it from the engine side.

gains i feel are indeed minimal, but felt mostly in the middle rpm range, 2000 to 4000. sounds is unbelievably awesome, i am ok spending $400 just to hear the roar...

peter