Well i always thought rain would be an issue, but how come air feed from bumpers dont suck in rain and destroy the engine? I got a spare bonnet I wanted to play with it so was thinking of cutting and blending in a little air feed as its seems hard to get a air feed in the valver engine bay! I feel my filters just sucking up hot air.
Drops of rain in the air that's sucked into the engine is not a problem.
Where rain is a problem with a ram-air type intake is where rain falls into the intake, collects in the air filter and piping then gets sucked into the engine when you start it.
So what you have to have is a section of pipe where the air coming in rises vertically.
That suggests you should have the air intake down load at the front. And that's in fact where the air pressure is highest. In race cars the best place to put the ram-air intake is just above the splitter. But the problem with that on a road car is if you ever have to drive through water. You don't want the air intake below water level or you'll suck water.
So you have to find the middle ground. Not so low that it could be underwater if you have to drive through a creek or down a flooded road, but below the level of the air filter so air has to climb vertically up into it to keep heavy rain and splashed water out, and certainly not on any upper surface like the top of the bonnet where water could come down into it.