I'm wanting to upgrade the sound system in my crewcab and would like to find out what others have done and maybe how they'd do anything different. I'd like to add speakers in the rear but don't want to have them below the back seat. I have the XL package so the inside door skins don't have the speaker grilles. Do the rear doors have speaker openings in the frame for the XLT and King Ranch packages? Are the factory speakers standard 6X9's or are they an odd size? Any tips would be helpful.