it was the very FIRST thing I did to mine, your engine and filter and battery get soaked when it rains anyways, all this stuff is designed so water wount have any harmful effects, unless of course you submerge it!
I remember seeing a photo from somewhere ...cold where the hood was covered with snow / frost. The only clear points (from heat) went straight from the side vent holes to the hood scoop. Hot air for the win!
If I could easily patch my hood so it *didn't* have the side vents I'd do it. Probably cost me a bajillion dollars at a body shop though!
Keep them open. The positive terimnal has that red little cover thingy.
But if you're not comfortable with them open. Do this mod first Hood vent Spacers
I did the spacers first. then just went to simple open.
open for summer, close for winter. im not worried about my car getting hot in the winter, and since it rains like crazy up here and i go snowboarding all winter, id rather have the covers on just to keep my engine bay a bit cleaner...