I'm about to use a hole saw on the door and was wondering if anyone mounted tweeters in the sloped marked in green on the pic.

 

Did you at least test fit it? Did you take off the panel to see if there are any obstructions behind it that would prevent it? Answer those questions and you'll probably have your answer.

 

Just got the car last week. I heard taking off and putting back the del door panel is a chore. Something about plastic screws snapping off. I drilled an accord after asking the same question. That install was fine without door panel removal. I might take it off and test, but hope to hear some feedback first.