Extra cars:
     Choose Begin Career and register with one of these names:

CHAO BROS - Indy cars
     PEACEFUL OCEAN - Stock cars

Slower Opponents
     Use    a    hex   editor   and   change   the   value   in   file
\data\tracks\trackname.cnf.  for  AI_CAR_SPEED: a value of 100 is real
slow,  350-450  for  most tracks. You can also just subtract 100 or so
for an easier race. for eample: 458 change to 358, etc.