Hi, seems very likely this car has been mapped. Unless the previous owner was a show off like me, who just wanted bad ass brakes.
And also, could possibly have been modded previously, most guys tend to put the car back to stock and sell parts seperate to get their money back.
Should you be looking for a sat nav, i might have the kenwood dnx520vbt for sale soon. Its double din, fits the mk5 golf perfectly, got bluetooth, nav, dvd player, tv (needs tuner), radio, microphone etc.