Easy game cheat: Buy any car, go to garage->tuning and set 6,5,4 gears to max, and then slowly decrease others but all keep to the right. Friction set max to temperature. Now go to options and uncheck: Enable clutch & Enable No-Gas.
Proceed to race. From start, press and hold spacebar and keep pressing the "N" quickly. You will have massive acceleration even if you have no nitro. If you have strong engine you dont even need to shift perfectly, just go and shift the 6th gear right after few meters.
With this technique you can easily beat on Pink Slip the McLaren F1 with Honda Civic.