@guyinnrw
If you haven't already, look at the 'compare' link i posted above. For instance, over the 350 the 660 has 3D Buildings, Garmin Lock, Picture Viewer, Audio Book & MP3 player, and 2-way BT (350 has 'normal' BT only). Both have LA with JCV and are Traffic Receiver capable. Neither has Voice-activated Navigation so don't use ASR files. Curiously 350 has Garmin Locate, Exit Services and Alarm Clock which 660 lacks. But this is now VERY much OT so best don't post again with questions about zumo specifically, only about the map and associated files. NP we all make mistakes, especially me & sometimes even Giomen! LOL.