In outback level at the first tunnel take a hard right and the is a wall that says 'Keep Out', go through it and you will be in a railroad tunnel, a nice shortcut.
Dodge Viper GTS
Get 2 million points to unlock the NFS edition of the Dodge Viper GTS.
Ferrari F50
Lead a single race, full grid, advanced, for eight laps to unlock the NFS edition of the Ferrari F50.
Lamborgini Diablo 6.0 VT
Get 2.5 million points to unlock the NFS edition of the Lamborghini Diablo.
Lamborghini Murcielago
Get 3 million points to unlock the NFS edition of the Lamborghini Murcielago.
McLaren F1 LM
Win the World Championship to unlock the NFS edition of the McLaren F1 LM.
Extra points
If you see a police car ahead, ram it to get him to chase you. Lose the police car and you will get extra points for a hit-and-run. Look for the dirt road shortcuts to lose the police and get ahead of other drivers. Also, choose to be the police in Hot Pursuit mode. You will get 25,000 points each time you complete one mini-mission.
Get more money
A way to get more money is to take third place in a race. Then do the race again and take second. Then after that take first. Each time you do it you get money from 3rd place, and 2nd place instead of just first. So you get more money doing it this way then just takin first.
Go faster
A simple way to go faster is to go straighter, but there are a lot of turns. Now a way to turn easyer is to hold down the "R" button when you turn. That will make you turn better and go faster.