As far as the front dash speakers go, I am under the understanding that 5.25" will fit w/ out a problem -just have to 'core' out the hole slightly larger.

5.25" will also fit in the rear this way as well, but I would think you might be able to put 6.5" in this location. Don't know this for sure though, have not yet haad the oppertunity to look over the speakers in my car yet -concentrating on programming the computer for it

As far as the subs in the doors? I don't have any idea. But common practice is to lose the first aid kit and fire the sub through there -I personally have my own reservations about this, but most people seem to do it this way.

Hope that might give a little more insight to you.