914

The 914 airbox comes equipped with drainage; however, those drains are for fuel that enters the airbox if the float valve doesn't work properly.
If the engine ingests a lot of water, then yes, it can cause damage. Some people design a baffle or a shroud around the air filter to protect it from getting soaked while operating in the rain.

Rotax also states to use a filter element that will not restrict the flow when in contact with water. With that said, it would probably take a torrential downpour for it to cause issues...I would be more concerned with icing at that point!

It's difficult to say what you should do with your aircraft and cowl design without seeing and testing it.

Hi Greg (fellow Aussie)

In addition to the above advice; I would question why you have  "air intake is a scoop feeding into the turbo"- In general (standard/unmodified) turbos deliver as much air pressure as your engine will ever require for best engine performance/longevity.

Trying to improve on your turbos's performance by accessing "ram" air does not usually have a positive/or any outcome. Check out the diesel (almost all turboed) trucks - the factory standard ones never have the air inlet facing into wind (direction of travel). Only the owner operated ones with aftermarket air inlets have them facing into wind, in the vain hope of greater performance - an optical/aesthetic enhancement at best.