JJ:
I thought the same thing (about hacking up the airbox) for the longest time. Mainly because I viewed it as a change which couldn't be reversed. But after a full 2 years of riding it (original owner) and doing everything to it I could to get more power and better response (short of singing it a lullaby)

I decided it made sense. Anytime you can get more air into the combustion chamber, that means you can increase the amount of fuel. This argument just made sense to me so much that one night I went in the garage and just plain did it. Only took all of about 20 minutes to do, but have enjoyed the results every ride since. Yes it does expose more surface area of the air filter to incoming dirt, but if/when you are comfortable doing the cut, wait till you see how much more air does get pulled into the airbox (shows up as a square patch of dirt on the top of the filter, just below the square hole you cut).

I was surprised to see it "want" that much more air. But it puts it to good use.
So while it seems extreme, if you compare it to a 250R, it's actually being choked, since all the race bikes have a large filter access opening beneath the seat, where all their air enters in. In comparasin, the square hole you make will actually be smaller than the race bike's.
Just some food for thought. It's never fun taking a knife to a new anything, except when it produces results you wish you had benefitted from months and months earlier!
Happy slice and dice (well maybe someday you will)!
matt