I made a really sweet setup by myself, and it cost me around $10. I used some shelving brackets, bolts, washers, and some e-z nuts to create the bracketry. Surprisingly enough there are very easy mounting points already pre-existing to carry this out.
I then took the bottom piece of a plastic jug (rectangular, has to be the right size) and cut a hole in the center, to which I simply inserted flex tubing. I painted the 'scoop' flat black, and you LITERALLY could not see the thing, it was located adjacent to the foglight behind the front bumper. It was a pretty sweet little setup.
With anything like that you are gonna get bugs and water, even if it's an above-the-hood scoop. With the setup I created, you don't have to worry about standing water, unless you are trying to ford rivers. You can go through water-filled dips and it sits high enough to stay out. Road crap wasn't really a problem.
The important part- did it work? I'm sure it didn't hurt. Any time you can get fresh air to the filter it helps. Because it's not as direct, it's likely not going to help as much as pulling your headlight, which actually does help a fair amount. Of course there was no SOTP gain, the gains were only theoretical but they *should* be there, no matter how small.
I can give some further info on exactly how to construct your own, if there is any interest. Just thought I'd chime in.