Replacing std speakers, not bose, to better ones?

[NightOwl]

Not surprisingly there is a thought spinning in my head, what if? So I've been looking at some alternative 2-way component speakers and found there is actually not many to chose from because most of them are too deep. But looking at the back side of the door panel shows there is a ring there that should meet the speaker. So then I've been wondering, is it possible to mount the speaker even further out from the door that the stock speaker by modifying this ring? If so, then it opens up a whole lot of speakers. I would not like to mount the speaker from the outside of the door panel, then it would look too much home made. Curiouser and curiouser, as the cat said...