The daylight clarity of the Garmin is very good. I have had a 660 and now the 665 and had no complaints on either.
My 665 has the XM radio in it, the output of the GPS and XM come out one plug, its plugged into the aux jack of the bike radio so everything comes thru the speakers. I have never tired to have the garmin giving directions thru its little speaker, I usually have the music too loud for that. I have the "navibitch" muted anyway, when I'm using it as a route, I pay attention to the visual prompts on the unit instead of the annoying voice commands. I go "off route" quite often so its always recalculating.
Both units can have up to 16GB micro SD card and can be used as an MP3 player as well.
I dont know if the Victory 660 mount would allow commands to come thru if you're listening to something else, I think thats how its supposed to work, but I have no experience with it.
Ride Safe, Ride Often
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