Cut the doors and put the 6.5s there.
That's one option, but you'll want plate speakers in the dash to bring the sound stage up.
"Quality is king" when it comes to setting up the front sound stage. Especially the 4X6's. You will hear those over a set in the doors.
Also, don't pump a lot of bass to either set of speakers. They will do nothing but pop at you.
A dedicated sub will be needed for bass.
Good luck!