I had the exact same set up in my cavi........6 1/2 " front door speakers.
Didn't have to cut a hole in the door at all or in the door panel.
Cheap fix........get a 3/4" to 1" piece of plywood and cut a hole in it to accept the 6 1/2 s. using sheet metal screws attach your new "adapter ring" to the inside of the door frame (you have to take the interior door panel off completely) and mount the speaker. You may have to trim the plywood some to make the "ring" but this way you don't have to go cutting metal.......and the speaker should fit just fine.
This was on a '97, but I doubt much has changed inside the doors.......if it has, then ignore my suggestion.