My 2006 A3 came with the sharkfin antenna mounted, even though it didn't have the Nav system. There's a compartment in the trunk for a Sirius/XM receiver, and the antenna cables for that are in place. I wonder if the GPS antenna cable can be found somewhere else? When I did the RNS-E install, I didn't see it behind the radio. Any ideas where I could look? Or is it unlikely to be anywhere? Are there versions of the sharkfin without GPS receiver?