I currently have a pair of Alpine SPS-600 coaxial speakers in the doors and I plan to replace those with components soon. Right now I am agonizing as to if I should make baffles and mount them to the sheet metal in the door OR just mount the components to the door panel like the factory speakers were mounted. If I do decide to go the baffle route, I need some suggestions as to how thick to go and still have the door panel fit properly.

If anyone has made baffles can you help me out with the dimensions? My main concern is mounting speakers to flimsy plastic although I guess I could use t-nuts, bolts, or masonite screws with the plastic retainers.