Replacing standard head unit with another standard head unit
 

I have an 2006 mazda 3 and I have the single cd player. I would like to exchange it with a factory stock 6 cd changer. Im reading that my local mazda dealer may have to reprogram the unit once installed. Is there anyone her that has done this, or know anything about it?

No, the dealer doesn't need to program anything, you simply remove the old one and install the new one.

Note that you will need a HU from '06-'09 to work. The LCD was wired differently in '04-'05. If you get a 6CD from '06-'08 then you can unlock the DIS by pushing and holding the CD and FM buttons.

Thank you IC, i just had this done this weekend. I changed from a single CD player to a six CD changer. It was just remove the old and insert the new. No dealer programming. The six CD player was a factory unit.