Juiced

All cars:
Enter PINT as a code at the cheats screen to unlock all cars in arcade and custom modes. Enter PING as a code in the pre-release version of the game.
and JORDI.

More money:
Enter FAST as a code in the pre-release version of the game.
Nazza_12.

Completion bonuses:
Get a 100% completion in career mode to unlock the prototype mods for all cars in career mode and the Extreme Nitrous Series in Arcade Mode.
TONYHOTROD2000.

All Prototype parts:
Get 1,500 respect points from every CPU character.

Crew members:
Gain the indicated respect to unlock the corresponding crew member.

Amber: 350 Respect from A.W.B.

Chief: 400 Respect from Vixens

Vito: 650 Respect from Urban Maulerz

Arcade bonuses:
Complete the all the series in Arcade Mode, except the Extreme Nitrous Series, to unlock the Bronze, Silver, and Gold Prototype Challenge Series.
TONYHOTROD2000.

Hint: Easy money:
In career mode, go to your garage and do something with one of your cars (for example, switch a part or get a different paint job). The game should autosave. Then, go back to your race menu. Go in a sprint and bet all your money on one car that looks the fastest. It it does not win at least three races out of four, turn off the Xbox and turn it back on. It will load your last autosave. Try the same sprint again until you win then find a different sprint and start the entire process again.
seth walker.

Earn 600 respect from any CPU character. Then, call any character on your mobile phone. Race for pink slips with one of your less powerful cars. After you get there, sell it for extra money. Make sure you have more than one car in case you lose the race.
Ktmrider154.

On days off, host your own race. Choose a sprint and select Class 1 vehicles. You will get a Viper vs. Viper; Viper vs. Corvette Z06; or Corvette vs. Corvette, and only two drivers, Biggi and T.K. If you get the Viper vs. Corvette, put all of your money on the Viper (maximum bet of $500,000). Collect your money, and repeat. You can choose other classes, but the lower classes give you mixed car results. Generally, anything modern will beat any muscle car in a sprint. A Skyline will beat a Corvette with up to 25 more horsepower. Biggi is a better driver than T.K. Sue is a better driver than Biggi. T.K. cheats every chance that he gets. You can also use your track to get better parts. Just schedule a circuit in the class of the car you want parts for, let your crew do the driving, and use all the cash from betting on sprints to hook up your ride.
G-13.

Host your own race, then pick sprint. Use your own speedway as the track. Select "Watch Race" so that you can bet. T.K. and Biggi will always race against each other. Bet on the car with the higher horsepower. You will win about 98% of the time.
jay jay.

For extra money race for pink slips with CPU characters. After you defeat them and win the car, sell it. Make sure you have more than one car in case you lose.
Bill Barkley.

When you run practically out of money. sell all or your only car. You will start over with $30,000 as you did before you started the game. Then, host a number of sprints and bet everything you have. No matter what happens, if you lose you will get your money back.
BeeCee38.

Note: This trick will work for some, but not all cars. If you are running low on cash, go to the dealership. A few of the cars that are in bad condition (used vehicles in poor condition) can be purchased then repaired in your workshop. They can then be sold for about $2,000 to $5,000 more.
Lpfan636.

When you start with the $30,000 the game gives you, go to host your own event and choose sprint. Choose the Class 1 car group. The first few times it will be Bigi vs. T.K. Always bet on the Viper. Repeat this until it starts giving Viper vs. Viper, etc. Switch to Class 4 and it will usually be Lancer vs. Camaro, Mustang etc. Always bet on the Lancer or newer car. Repeat this until the same cars appear. Go back to Class 1. It should now be Viper vs. Corvette again. Bet on the Viper. If it continuously gives you the same cars, do a few races or save and restart your system.
Locklear61501.

In career mode, go to the calendar and select an empty date. This will make you host an event. Set the bhp of the cars to the top and make the make of car Dodge. You should get a Viper against a Charger. If this happens, put all of your money on the Viper. it will win and you will win the bet.
michael coppen.

Race and earn a bit of money, then host sprint races at your won track. Have Class 1 racing, and bet all your money on the Viper. If there are two of the same car, bet on the blue one.
bvfnrubnbJim Brown.

It is best to do this towards the beginning of a new game or profile. Start a new race on a blank day on the calendar. Make the race a Sprint and make it Class One Vehicles. The cost for this will be $1,000. There will usually be two racers at the betting screen and they will have either a Viper GTS or a Corvette. Bet on the Viper GTS. It is important that those two cars are in the race. If you get two of the same car, abandon the race and do not bet. The reason for this is that the Viper GTS has 993 bhp (the highest one in this mode), and the Corvette has 907 bhp. It takes some time and is not recommended for someone with too little money.
Taylor Mac.

Hint: Easy wins:
Get three of the CRX mod it until you have 199 hp. Let Amber, Vito, and Chief race the free sprints until they get full skills. Then , use them in a 2-2-2 or a 3-3 circuit race.
Flashjr212.

Go into the workshop. Select a car and make it the top of a class (199 bhp, 299 bhp etc.). Then, go to the calendar and choose a sprint in the class that the car is in. Enter the race and choose one of your crew to race. When in the race, set mentality to high and they should win.
MDOGG.

Hint: Easy mods:
When you have a certain car you want to upgrade quickly, go to host your own event circuit or point to point Do one lap and your car's horsepower that you want upgraded. Choose to enter the event. Race and bet only if you can win. No matter where you finish, you will unlock a mod each time. Make sure you finish the race. Only do one lap, as it does not take as long. When you have your car fully done, race for pink slips.
Locklear61501.

Hint: More efficient turns:
While you are about to do a turn you must slow your car while entering it. When you are exiting, nitrous out for the best and most accurate results in that turn.
chick_hogger123.

Hint: Recommended cars:
If you want to get the most out of your days racing, you should get a car in every class. For example, get a Civic DX for Class 8, an Acura RSX Type R for Class 7, a Celica SS II for Class 6, a Skyline GTR for Class 5, a 300GT for Class 4, a Corvette Z06 for Class 3, and a Viper for Class 2 or 1. Note: The faster the car and higher the class of the car, the more uncontrollable it is.
CrazyElf874.

Hint: Regaining composure:
If you are allowing one of your crew members to race and their composure is one red, instead of going on to medium, go on to low because it regains twice as fast. This means they will have more time to race on high. Do not bet your money all at once unless you really need too.
beniscool08.

Glitch: Flying car:
Start with a Viper GTS fully tuned and go to the oval track. Drive about 210 mph. When you are about to turn, turn the other way into the wall. Hit the nitrous and hold it while still turning into the wall. If done correctly, you should go up and fly. You must be in the dirt part of the turn. Try using the nitrous two seconds before hitting the wall and hit the wall (wire fence) at about a 30 degree angle.
Tom Gates.