Even with Jules' plastic insert on the drivers side, and aquarium filter material on each end fine debris will still get in, if the plenum tubes have not been cropped off to about 15mm at a 45degree angle you will eventually get water in the plenums have no doubt about that, it may take time but it will happen.
The spy hole mod will let you rod the plenums in a matter of minutes, and checked once week is not hard, so my advice is do the spy hole mod and cut the plenum tube, access is from under the car only.
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Spy hole mod
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Inner wing aquarium sponge and tubes
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