Got the Uno to send back some live GPS data, this time displayed as a converted KML track. Took this live, but interference from both rc TX and the xBee made for a REALLY bad connection. Seriously had a better connection going through two houses. Shows that the maximum speed achieved was 92.2 km/h. Probably a result of connecting the gap between two disconnected routes, but seemed steady on the graph. The flats are averages calculated by Google Earth to fill in the gaps:
What was the name of the program you used to send the KML files to Google Earth?
Earth Bridge
Earth Bridge converts a live NMEA feed to a KML format. Google updates its KML track at regular intervals, each time adding any extra points in the track from the KML file.
Earth bridge is mentioned in the previous post.