Ferrari
To unlock the Ferrari press Up, Down(2), R1, L1, Left, Up(2)

How to go really fast in less than 5 secs!
*This doesn't on multiplayer.

Press the brakes until your at 0 mph or km/h then hit the gas and the nitro at the same time.

I did this with the Racing Rex and reached 460 km/h (287,5 mph)

Fast refuel
You know when you have to go to the pit stop , and you run out of fuel? well you could refuel fast by holding the right analog R3 button and you will refuel faster!

How to get 2,000,000,000
At the main menu press L1, L2, Triangle, R1, R2

How to get credits fast in grand prix
First: Sell your fuel until it reaches 15%

Second: Go in the race and go for a pit stop. Fuel your car until it reaches 100% percent

Third: go back to the place where you sell your fuel and sell all of it until it reaches 15% By doing this you can earn millions just follow the three steps
it does take kind of a while but its a risk your gonna have to take

Unlock a new car (NOT IN GRAND PRIX)
Bored of having slow cars well here's a way to unlock new car: you have to do 101 laps in free run I did this twice

Dt racer
To get a gigantic turbo use the e brake and gas until your going 2mph let go of the brake and use turbo right after.

Dont crash
Drive fast then when the screen starts to deform keep driving a little after you will start turning to hit the wall right then push the analog a LITTLE TINY BIT to the side you want to turn I really recommend that you don't push it hard if you don't wanna HIT THE WALL

JuiceeJosh Rocks

GP cheat
Go buy any car you can afford, sell all the fuel, then sell the car. Repeat until you get what credits you want. Its not fast nor fun, but it is not risky and if you continue, you could actually get millions doing this... for about 10,000 times. Also after any race, sell the fuel you got, if not at 15% (thus just continue) then sell the car and buy it again.