First some important infos:
 

• There is NO cheat to get money so far. Anybody telling you anything else is lying.

• You can't ride faster than 430 km/h at the High Speed Course! My fastest Speed so far is 418 km/h with an MITSUBISHI GTO MR and exactly the same speed with an NISSAN R33 Skyline V-spec and I am absolutely sure that a speed higher than 430 km/h is absolutely IMPOSSIBLE.

• The only little "cheat" known so far is that you can tune 2 equal cars with one set of parts! Simply upgrade one car, then change to the other, go to the car settings and you can fit the parts from the other car to this one (except racebody, weight reduction and port polishing)!