I've tried to collect all the information I can about unlocking everything in Burnout Legends, so appologies if I've missed anything. However, here is my attempt at a walkthrough (of sorts) for the best PSP game to date:

Types of Tour Races
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Race - Pretty much a basic racing game.

Face-Off - Similar to Race but against only one other car.

Burning Lap- Usually with a special car that you’ve unlocked. Basically, do the fastest lap you can.

Pursuit-Just like Chase HQ (and my personal favourite). Drive a police car, catch up with the bad guy and smash them till they’re damaged enough to stop. Cool.

Road Rage- Destroy as many other cars as possible while avoiding getting damaged yourself. Quite a fun little race.

Eliminator – Eliminate the last person on each lap until only the top 3 are left.


Stuff to Unlock
===============
Unlocking Cars
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New cars for the standalone mode are unlocked after getting a certain number of points or cash from races and crashes. These cannot be used in the Tour mode though.

Cars unlocked in Tour:
Oval Special Racer - Get all Signature Takedowns.
Classic Hot Rod - Get all Special Event Postcards.
Custom Coupe Ultimate - Get a Medal in every Race Event.
Euro Circuit Racer - Get all Takedown Trophies.
US Circuit Racer - Get the Gold in Super GP.
World Circuit Racer - Get the Gold in Special GP.
Cop Racer - Get Gold in all Pursuit Events.
Gangster Boss- Get Gold in all Race Events (tough challenge)
Compact Cop - Get the Bronze in Silver Lake or Airport T1 & T2 Pursuit.
Legend Compact – Get the Gold in Interstate Loop Legend Face-Off.
Gangster Legend – Get the Gold in Palm Bay Legend Face-Off.
Dominator Compact - Get 10,000 Burnout Points.
Tuned Compact – Get the 5 Gold Medals.
Assassin Compact - Get 15 Takedowns.
Muscle Cop - Get the Bronze in Harbour Town or Sunrrise Pursuit.
Classic Legend - Get the Gold in Big Surf Legend Face-Off.
Legend J Muscle - Get the Gold in Airport T1 & T2 Legend Face-Off.
Dominator Muscle - Get 25,000 Burnout Points.
Tuned Muscle - Get 20 Gold Medals
Assassin Muscle - Get 30 Takedowns.
Coupe Cop - Get the Bronze in Big Surf Shore or Sunrise Pursuit.
Legend Pick-up - Get the Gold in Airport 3 Legend Face-Off.
Legend SUV - Get the Gold in Sunrise Legend Face-Off.
Dominator Coupe - Get 50,000 Burnout Points.
Tuned Coupe - Get 40 Gold Medals.
Assassin Coupe - Get 60 Takedowns.
Sport Cop - Get the Bronze in Dockside or Island Paradise Pursuit.
Legend Oval Racer - Get the Gold in Sunrise Valley Legend Face-Off.
Legend Roadster - Get the Gold in Big Surf Shore Legend Face-Off.
Domniator Sports – Get 100,000 Burnout Points.
Tuned Sports – Get 50 Gold Medals.
Assassin Sports - Get 100 Takedowns.
Super Cop - Get the Bronze in Winter City or Island Paradise Pursuit.
Legend Super Car - Get the Gold in Airport 3 Legend Face-Off.
Legend Hot Rod - Get the Gold in Palm Bay Legend Face-Off.
Dominator Super - Get 200,000 Burnout Points.
Tuned Super - Get 75 gold medals.
Assassin Super - Get 150 Takedowns.

Signature Takedowns
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There are some signature takedowns which will give you a bonus, these are special takedowns that need to be performed in the Tour mode. You also win trophies for some takedowns, all of which can be viewed in the menu.

Crash Headlines
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You can get news headlines by getting a certain amount of cash on the crash mode.

Bayside Blitz = Get $800,000 or more in Waterfront
Downtown Demolition = Get $500,000 or more in Downtown
Silver Lake Lunacy = Get $520,000 or more in Silver Lake
Winter City Frozen = Get $550,000 or more in Winter City
Alpine Smash = Get $650,000 or more in Alpine
Rivera Wreck = Get $575,000 or more in Rivera
Vineyard Crushed = Get $800,000 or more in Vineyard
Golden City Madness = Get $600,000 or more in Golden City
Dockside Ruin = Get $600,000 or more in Dockside
Trouble in Paradise = Get $600,000 or more in Island Paradise


Track List
==========
USA Tracks
The Waterfront
Downtown
Silver Lake
Airport T1 & T2
Airport T3
Palm Bar Marina
Big Surf Shore
Interstate Loop
Sunrise Valley

Europe Tracks
Winter City
Alpine
Rivera
The Vine Yard
Harbour Town

Far East Tracks
Golden City
Dockside
Island Paradise

Collect all the Legend Face-Off cars to unlock mirror mode for single events