If you do not know what and who MoTeC is, go to this site:
http://software.motec.com.au/release/
download the file
i2pro
and install it (harmless, really!).
It comes with a video (running automatically at first startup) illustrating all screens and options. You will see quickly that you have left the realms of PC games here and entered the land of professional data analysis. This feature is what sets GTR apart from every other racing sim's setup options.