OK, I have the Pre+ on ATT. If the ATT navigation is a full install with all maps and TTS files, and a decent number of POI then it should/could be as little as 2Gig and as much as 4Gig. Is there only a downloader installed on the phone which grabs the map data as needed. There *could* be TTS and standard voice guidance installed but I doubt that too. I've been looking with Internalz and so far have found a few instances of "Telenav" but nothing in there. I put about 7 gig or so music on there so I now have approx 7 gig or so left, with 14 gig original space.
Can anyone tell me the extent of the ATT Nav install? I've never used it (don't want to even get started with trial/invasive registration w/ATT etc.) so I don't know how well it even works.