Loading new maps like topo and street maps

Try DCRainmaker's link. Almost certainly going to be the same as the 520. http://www.dcrainmaker.com/2013/05/download-garmin-705800810.html

The Edge 1000 would be a better reference. On the 520 you need to fool the unit by replacing the default map. On the 1000 and 820 you can add additional maps.

The Edge 1000 would be a better reference. On the 520 you need to fool the unit by replacing the default map. On the 1000 and 820 you can add additional maps.

Good Point.

This might be a better article http://www.dcrainmaker.com/2013/05/download-garmin-705800810.html

That's the same link, isn't it?