Just give all drivers racing in the mardave modified class written instructions when they book in.
To be honest even in the tin can class you can cheat and use faster tin cans which look like the mardave motors. It is all down to honesty really.
Look what happened to lance armstrong cheats do not prosper.
Ive raced against kev and dobs for years and they have never really had faster cars they were just faster getting around the track due to better setups and better driving.I hate them both lol
