Adjust Camera Cheat
Complete the Special Stage in Chapter 8.
Easy Kudos
Enter a "Hot Lap" trial in any chapter, a trial in which you only need to beat a lap time, not one of the average times. Start the race, then on the first lap, get the time needed. You now have passed the stage, but do not end the second lap. Find a good, straight portion of road. You get Kudos for turning with the handbrake. Go to one side of the road as fast as you can. As you are approaching, do a 180 degrees turn using the handbrake. If done correctly, the words "Wey Hey" should appear on the screen. Next, drive the way you are facing to the other side and do the same. When moving the wrong way, you need to spin 180 degrees in order to get the Kudos. Just keep repeating this, then finish the race. For every five minutes that you do this, you will get approximately 1000 Kudos. There is no time limit. The best city for doing this trick is San Francisco, as it has wide roads. Play jokers to get more points -- if you do this for 20 minutes with a joker, you can get more than 8000 Kudos in just one race.
Free Roam mode
Beat all One on One Challenges in Chapter 25 to get Free Roam Mode for each area of the 3 cities.
Get All Cars
From the Title screen, press a,x,y and R at the same time to unlock all cars (they will appear in your saved game).
Honda S2000
Complete Quest mode once to unlock the Honda S2000.
London Cab
Complete the Special Stage in the last event in Chapter 6.
Opel OPC
Complete the Special Stage in the 9th event in the Chapter 1.
Porsche 911
Complete Quest mode twice to unlock the Porsche 911.