I found this while advancing through the career. Its not a cheat, but simply a quicker way of getting to the level you desire. This is what you need to do:
1. Unlock tier 3 and buy the Lamborghini Murcielago LP640 and build up enough money to max out it's stats and buy works. Then tune the front end downforce (Aerodynamics) to 14 instead of 4.
2. Enter the Endurance events once you have unlocked them and select the "Race at Hazyview Eight" event.
3. Once you have entered, do whatever it takes to rack up as many points as you can. Try mostlyfor corner sliding, as that raises your score by 2,000 to 3,000 each time. Try to hit other racers aswell, because this also gives you about 2,500 points each time.
You will notice that the race is 30 laps long, but that isn't as bad as it sounds. The track itself is only 0.31 miles and you will most likely finish each lap in 16-20 seconds. I personally complete each in 16.3 seconds, and I've finished the race in 10 minutes, 20 seconds. And by the timeyou finish, you should have around 10,000 to 15,000 overall points. This amout can easily bump you up 1, 2, or even 3 levels at a time, but 3 is not guaranteed if you're a higher level.
I have been doing this for the past day and a half, not nonstop, and I've went from being level 23, to level 49. I can promise you will have the same result. But the points scored also depends on how good you are at the game and if you can do exactly what is required to rack up those points.
These are the main categories to put most of your effort into when trying to get points:
Clean Sector- Complete a sector of the race without making contact with opponents or going off the track
Clean Overtake- Pass an opponent without making contact
Dirty Overtake- Pass an opponent by forcing your way through
Corner Slide- Drifting around corners without leaving the track
Trade Paint- Simply hitting or ramming an opponent
Spin Opponent- Cause an opponent to spin out or go off the track after you have hit or rammed them.
Hope I helped; Happy Leveling!!
Added by: dragonblayd Mar 21st 2010, ID#5606