Just an FYI..the Garmin nuvi's..and maybe all of the GPS units that have the Lifetime Maps and Live Traffic Up-daters have the antenna for the incoming data in the charging wire, that feeds from the 12v dash power source. Just note that the plug in module is quite large and on Fords the end of the plug-in adapter is really really close to the working end of the transmission shifter. I have talked to Garmin and they acknowledge the issue with no intention of changing anything. One suggestion from Garmin was to purchase one of the 12V adapters from Radio Shack with the multiple plugs, thus moving the adapter out of hands/harms way. I haven't pursued this yet, but likely will.
Gary Haupt