BS4TV will let you import your GTech Pro data and replay it on a blue screen. You can then use your favorite video editing software to combine this replay with your track video using the blue screen chroma-key technique. The result:
Search "Videos" using the keyword BS4TV to see videos that used this software to turn interesting track videos into much much more.
BS4TV supports the GTech Pro drag race and road race modes. Different displays are available for each mode, and in mode a bar gauge and dial gauge display are available. In addition, each bject on these screens can be customized to suit your tastes.
BS4TV also allows you to enter additional vehicle data so you can make pitch and roll corrections, correct the initial speed for cases where you were already rolling before data recording was started.. You can specify time offsets to let you shift the actual time so that the lap timer starts at a particular event, such as crossing the start line. If you'd prefer to use your gearing, tire diameter, and RPM to estimate speed, you can enter this data as well.
To support all this, BS4TV provides charts of your data and tables where you can go to any data point and add comments that can be displayed on the screen, or enter your gear selection, useful in one of the methods available for estimating your speed. You can zoom and scroll the charts, and clicking a data point will scroll down through the tables to help you quickly locate that point.
BS4TV is currently in the later stages of development and testing but should be available soon.