Never had Regensberg syndrome, mine sits above the metal beam as all the rest, only time the unit has ever had problems locating was when I first installed the unit and it took it awhile to figure out I wasn't in Tewkesbury (clearly where the unit was removed from a car)
DOnt think the my-gti one does have two gps antennas, I imagine the other cable goes to either video input device or as he is an AUS some form of different radio antenna is it Cirrus in the USA???