If you want both miles and meters in one overlay, that is not possible with the current version (2.7.0). You can change the overall settings to metric. As I don't have a MAC you'll have to search the forum as the question is asked (and answered) more than once. (or maybe someone will answer it here again)
Just took the Elite for its first test ride. A few wishes:
1. Allow the camera to take speed from my wheel magnet via the ANT+ sensor. Riding among buildings and under bridges throws the speed overlay off. Apparently I got up to 160km/h on my bike!!!
2. When my VIRB Elite syncs up to Garmin Connect, keep track of the kms and activities just like my Edge 510 does.
3. A mount to put on the chain stay. The standard ones either hit on shoes, wheel, brakes plus the fact the camera is mounted on its side.
4. Elevation corrections like Edge 510 in Garmin Connect, which then goes back into the Data Overlay of the footage