OP, read the thread that GPB posted. It's extremely informative and the actual process for updating the maps is easy.
1.) Download the NAV update via torrent - transfer the files onto a thumb drive (your drive must be at least 32gb and be in the FAT32 format). The actual maps files are around 22gb in size I believe. I was lucky enough to find a member in my area who hooked me up with the drive.
2.) Email Sergej regarding the FSC code. You need to enter this code during the beginning of the update in your car. He charges a reasonable price, and is very responsive.
3.) pop in the thumb drive and follow the steps. Took about an hour for me, and for many other members no problem.
4.) Enjoy your new maps, without getting robbed by the dealer.
2010 335i xdrive M sport - Sold