Boxcutter FTW. Takes 30 seconds... if you're worried about it, you can always heat the boxcutter blade with a torch (or I suppose a lighter?).
There is a waffle-like piece of thicker plastic behind the bumper cover. It's a bit more difficult to cut through... and by difficult, I mean still easy, just thicker than the thin plastic of the cover. I heated the blade to cut through that, just because.
As for the charcoal box... it shows, but as you can see, it doesn't stand out TOO much. Someone at one point suggested I spraypaint it flat black... but meh, I'm not TOO worried about it.