The speakers do the job for average people, but those of us who have heard good systems know it could be way better. Replacing speakers wouldn't be a bad idea...does anyone know how to get the door panels off ? I'd like to see a tutorial or diagram so that I don't break something getting them off.

Buying higher wattage speakers is fine, but make sure to get something with a relatively high sensitivity rating. The improvements you'd likely see from aftermarket speakers is better frequency response. and dynamic range.