These should be entered as drivers name in create driver screen: 
FEATHER                 for 3/4 gravity it means when you flip 
                        over you can't get back up 
FLOT                    for 1/2 gravity 
STONE                   for twice gravity 
RADBRAD                 for better gravity 
BANZAI                  for no car collisions 
WHEELS                  for just wheels you have no body 
                        and so do the other people 
FAT WHEELS              for fat back wheels 
WINNER                  for as though you won 
IMMORTAL                for invincible 
GEK                     for 2 lap races 
PUSHBUTT                for dual-analog controls