Great mod! In fact I did this exact same thing on my 180SX 2 years ago when I got it! I bought a Vibrant MAF adaptor (you called it a 'bracket' i think...) and bought the hugest K&N air intake that would fit!
Not that anybody on this forum is interested... but the parts I used were the Vibrant P# 1997 MAF adaptor and a huge K&N RE-0930 Air filter! In fact it's so big, now that I've stuffed more stuff in that area of my engine bay, it's getting squished on one side...
I think at the time I paid about $30 for the adaptor, and $50 for the filter + GST.
If you don't have the ABS in your Subie I highly recommend to get a huge filter. You want the lowest restriction possible that you can reasonably afford. That vent you have on your hood is dope! I'm going to have to mod my hood and drop one in like that. I don't even think you'll need much of a CAI extension with that! You will continually get a nice fresh air supply from outside your car with that. That's probably why Subaru designed it there in the first place... So that all you need to do is remove the stock airbox and you're one step closer to WRC performance!
I'm not an expert, but dosen't Hydro-lock only occur when you completely submerge the intake in water? Then the engine sucks in water, which isn't easily compressible, and blamo...
Surely a couple of droplets of water, or even rain on the filter, aren't that serious... They'll just get vaporized in the engine intake/head before combustion? (almost the same as setting up water/methanol injection?)
