For experimenting, you might want to make a

Fake Roster

To remove the fake roster data, re-initialize the database, or click "Purge Data" and delete racers.

After testing or experimentation, you may wish to delete some or all of the data in the database.

Import Roster
Racing Groups
Import Awards
Settings
 

If you have a saved prefs file,

Drop prefs file here

You may also want to visit the Scene Editor or the Playlist Editor