Sometimes we do see the differences between the GPS based driving line and the background image. Race Studio 3 defaults to the latest Google Earth image that is available at that track. But you do have the option in the upper right corner of the track map view to 'Click to change tile layer' and when you select that option you will see (currently) 7 different options and I suggest you try to see if any of those give you better results. (Bing, Here, ESRI, Street Maps, etc.)
Is it possible to calculate the best theoretical across multiple sessions? I see individual bests for each session rather than across all.
Is there a way to correct if there is an offset between the map and the gps data?
Sometimes we do see the differences between the GPS based driving line and the background image. Race Studio 3 defaults to the latest Google Earth image that is available at that track. But you do have the option in the upper right corner of the track map view to 'Click to change tile layer' and when you select that option you will see (currently) 7 different options and I suggest you try to see if any of those give you better results. (Bing, Here, ESRI, Street Maps, etc.)