Burnout 3: Takedown cheats and cheat codes for XBox

Boost on Start
Hold the gas while pressing the brakes. Your tires will smoking. 
Release the gas when you hear "GO!", then press it again.

Unlocking cars:
Choose your favorite track in world tour mode and race it repeatedly 
(do not retry). Continue, then repeat.

Change song:
Hold White + Black during game play to advance to the next song. 

Compact Types 1, 2, 3:
Available from the start of the compact race series. 

Super Types 1, 2, and 3:
Available from the start of the super race series. 

Unlock Muscle Types 1, 2, and 3:
Win a Gold Medal in the Silver Lake Compact Grand Prix. 

Unlock Coupe Types 1, 2, and 3:
Win a Gold Medal in the Waterfront Muscle Grand Prix. 

Unlock Sports Types 1, 2, and 3:
Win a Gold Medal in the Vineyard Coupe Grand Prix. 

Unlock Super Types 1, 2, and 3:
Available from the start of the super race series. 

Unlocakble cars:
Assassin Compact car: 15 Takedowns 
Assassin Muscle car: 30 Takedowns 
Assassin Coupe car: 60 Takedowns 
Assassin Sports car: 100 Takedowns 
Assassin Super car: 150 Takedowns 
Classic Hotrod: Reach a Gold Medal rank in all special events 
Custom Compact Car: Reach 10000 points in world tour mode 
Custom Coupe Car: Reach 50000 points in world tour mode 
Custom Muscle Car: Reach 25000 points in world tour mode 
Custom Sports Car: Reach 100000 points in world tour mode 
Custom Super Car: Reach 200000 points in world tour mode 
Compact DX Car: Reach 4 Gold Medals in world tour mode 
Muscle DX Car: Reach 10 Gold Medals in world tour mode 
Coupe DX Car: Reach 18 gold medals in world tour mode 
Sports DX Car: Reach 25 Gold Medals in world tour mode 
Super DX Car: Reach 32 Gold Medals in world tour mode 
Tuned Compact: Win on 1st place in Downtown Race 1 
Tuned Coupe: Win on 1st place in the Vineyard Face-Off 
Tuned Muscle: Win on 1st place in the Kings Of The Road Race 
Tuned Sports: Win on 1st place in the Continental Run Race 2 
Tuned Super: Win on 1st place in the Island Paradise Face-Off 
Modified Compact: Win on 1st place in the Waterfront Face-Off 
Modified Muscle: Win on 1st place in the Mountain Parkway Face-Off 1 
Modified Coupe: Win on 1st place in the Alpine Race 
Modified Sports: Win on 1st place in the Continental Run Face-Off 2 
Modified Super: Win on 1st place in the Golden City Face-Off 
Compact Prototype: Win on 1st place in the Lakeside Reachaway Face-Off 1 
Muscle Prototype: Win on 1st place in the Mountain Parkway Face-Off 2 
Coupe Prototype: Win on 1st place in the Continental Run Face-Off 1 
Sports Prototype: Win on 1st place in the Frozen Peak Face-Off 2 
Super Prototype: Win on 1st place in the Gold Medal GP 
Dominator Compact: Win on 1st place in the Kings Of The Road Face-Off 
Dominator Muscle: Win on 1st place in the Lakeside Reachaway Face-Off 2 
Dominator Coupe: Win on 1st place in the Frozen Peak Face-Off 1 
Dominator Sports: Win on 1st place in the Alpine Face-Off 
Dominator Super: Win on 1st place in the Dockside Face-Off 
Heavy Pickup: Reach $1 million in world tour mode 
4WD Racer: Reach $2 million in world tour mode 
SUV Deluxe: Reach $5 million in world tour mode 
4WD Heavy Duty: Reach $10 million in world tour mode 
B-Team Van: Reach $15 million in world tour mode 
INT Express Delivery Truck: Reach $20 million in world tour mode 
Tractor Cab: Reach $30 million in world tour mode 
Longnose Cab: Reach $50 million in world tour mode 
City Bus: Reach $70 million in world tour mode 
Trash Truck: Reach $90 million in world tour mode 
Fire Truck: Unlock all crash headlines in world tour mode 
Oval Racer Special: Unlock all signature takedowns 
Custom Coupe Ultimate: Win on 1st place in all crash events 
Euro-Circuit Racer: Unlock all takedown trophies 
Classic Hotrod: Unlock all special event postcards 
US Circuit Racer: Win on 1st place in Super GP 

Unlock Need For Speed Underground Cars
Finish all Crash Mode levels and reach Gold rating.
Then go to the car selection screen, hold White + Black while 
selecting a vehicle.

Unlock Trophies:
Finish all Advanced Takedown Targets - Get Advanced Takedown Trophy
Finish all Champion Takedown Targets - Get Champion Takedown Trophy
Finish all Easy Takedown Targets - Get Easy Takedown Trophy
Accumulate all Takedown Trophies - Get Euro Circuit Racer
Finish all Expert Takedown Targets - Get Expert Takedown Trophy