Use a trainer that has big money on it. That's what I did. Or use "unlockallthings" and then buy a fleet of the free Integra,mabe 10 or more and then sell them all. Also with "unlockallthings" you'll get 4 free cars,Viper,GTO,Cobalt,and 240sx...sell all 4.
Ok but how it seems i didn't make myself clear.
I am NOT using ANY cheats or trainers.
What car do you currently have?
For Grip i have Nissan 240NX
and for Drag i have Chevy Chevelle SS