Laptop to Nav Screen using Coastal Electronic Inc. LOCKPICK

My question..is why use street atlas

ok its a very good program

is the chevy navigation program, that bad
or is having SA notify you of way points you have set

you want or need the notifications, ok
just don't expect to get the same read ability, the same clarity and sharpness
the GM display is sharp enough,
BUT the composite video signal..will not have the same sharpness and detail that the laptop has