they will let you run a 6.5 comp set in the doors without cutting anything. You can also mount the tweeters on the surface of the doors with some strong double side velco that way you can remove them when your ready without leaving a hole there.
I got a pair of Pioneer 5x7s at a garage sale for $5. Pretty decent. They are now my rear fill.
But if you don't get lucky like that, how about the Phoenix Gold RSd coaxials? Everyone here raves about the component set, the coaxes can't be that bad.