Thanks BMW-North great tips, I am sure I will have to replace mine some day...

 

I'm betting you never need to replace them. These items seldom need replaced. Most often (on BMW's anyway) it's typically owner intervention that causes it. (Use of oil based air filter or the use of a non-compatible cleaning solvent)

I cleaned my old (AMv8) ones with carb cleaner/compressed air and they worked fine (Do not use brake cleaner) - but for $82 I replaced them with new and now have two spares (the originals).

 

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The factory power pack included not only the intake flaps but also a retune of the ecu. Without test data, it's hard to say which of these is the more impactful modification, but I suspect it's the ecu.

I agree with Richard that water intrusion needs to be minimized, but the risk of hydrolock is only present if the intake is completely submerged. Think about trying to pull water through a straw when only half of the straw opening is in the water or if there is a hole in the middle of the straw. All you get is air.

Evey time a car is driven in the rain the filters get wet, but there.is no risk to the engine. So I don't see drilling more holes in the intake or removing the box altogether as an increased risk of water intrusion damage.

Water is sometimes intentionally injected into the charge of an engine to cool the intake and resist detonation, so it is not inherently damaging to an engine to injest water, but of course this is in a controlled manner.

 

100% from the K& N. I know this all too well. Ask me how (not really - trust me).