i just picked up a used d3. it only came with the west coast nav disc, and i need the east coast nav disc. i see nav discs for sale all over ebay, but im curious, do i need the an OEM copy of the red east coast nav disc, or can i just run the green ones that say cndv-80mt on them that are like $15. the only thing throwing me is that its an "update disc", and im not really sure if its meant to update the system or if its a replacement to the red one. thanks.

Pretty certain that you can jump right into the green "update" disc. If the unit it running right now (everything 'cept east-coast nav), the unit has the original firmware installed and can accept the update disc.

The green disc are updates, if you have the east coast firm ware they will work for you. If not you will have to get the red east coast disc.