I've got Focal 6.5" speakers in my doors. They sound great. They did require a custom speaker box to be built, but that's really not a big deal for a good installer.

 

I have 5.25" Focals and installed with no mods. Focals can reproduce every note without distortion. If you feel sound is bright, get mid-bass component speakers. Something more affordable? Get MB Quart, make sure they are made in Germany. I have those on my BMW and sound great too.

 

I did 6.5" mid bass speakers in the Bose enclosure which I modified for the doors. Worked great, had big bass tight bass response. So good didn't really need a subwoofer in the rear.

 

^ did you use MDF/Birch/or ABS? good work by the way!

 

I used MDF that was treated with bed-liner spray.