I'd rather keep my wing, or maybe even put a more functional one but I'd really like to vent it properly but still keep it looking good

 

I was joking on the wing holes lol, don't actually do it or you'll have rain pouring into them. You can probably find some solution through rear quarterpanels or the floor, but I wouldn't recommend venting the trunk lid since you'll have to set up rain rails.

Do note that though, once you do find a way to vent it, your inner trunk will be more vunerable to dusts, gases, moist and insects, your stereo would have to be somewhat decent weatherproof and probably can't store anything in the trunk other than rugged items such as tools.

I honestly don't recommend the relocation, it might be functional and easy on a stripped out EG hatch but not the case for EVO. You planning on putting the aftermarket stereo doesn't make it any easier either.