Replacing speakers

[s2gordon]

Hi everyone.. I'm new to the group. I purchased an 03 Navi Ultimate a couple weeks ago. I'm in love with this truck I traded in a Mazda Portege5 for this beauty. Any way like the stereo and was hoping to get better sound by replacing the stock speakers I have the following questions

1. Where do i find instructions on taking the doors apart?
2. Any suggestions on a good replacement brand?
3. Anyone know of a good replacement for the factory subwoofer?

Thanks