The thing about adding filtering of some sort to the bottom hole is that it's cutting the flow to an extent and not doing anything more than the filter itself other than adding more filtering which also cuts down the air flow. In other words, nothing you do to that bottom hole is going to help w/o also eliminating the benefit it was done for in the first place. So if water is the issue, adding filtering isn't the fix because it will help, but also remove the benfits of drilling to a degree, and a degree which is probably linear as far as how much it keeps things out vs how much performance benefit. The way i see it, if water does find it's way in there, and i think it will, you should probably pass on that mod. i did it, but only because i don't ride when it's wet. And i can tell you that there IS a LOT more that gets in with the bottom drilled than w/o, water or whatever. Since i did the mod i have to clean the filter at least once every 6 weeks minimum or i begin to lose power, and i can see the debris thats stuck to the filer.. So if that much dirt/debris gets in thru the bottom you can imagine what happens in the rain.
