xbox360-DiRT 2

Bonus cars
Have a saved game file from the original DiRT to unlock the Subaru Impreza STi Group N with No Fear (Gold) Livery.

Have a saved game file from Grid to unlock the Subaru Impreza STi Group N with Ravenwest Livery.

Successfully complete the indicated event to unlock the corresponding car:

Colin McRae Challenge: 1995 Subaru Impreza WRX STi with chrome Colin McRae Livery
World Tour - Landrush: Toyota Stadium Truck
World Tour - Raid: Mitsubishi Pajero Dakar 1993
World Tour - Rally Cross: Ford RS200 Evolution
World Tour - Trailblazer: Dallenbach Special
X-Games - All Completed: Ford Escort MKII and MG Metro 6R4
X-Games - Asia: Mitsubishi Lancer Evolution with X-Games Livery for Trailblazer only
X-Games - Europe: Colin McRae R4 with X-Games Livery for Rallycross only
X-Games - North America: Subaru Impreza WRX STi with X-Games Livery for Rally only

Achievements
Accomplish the indicated achievement to get the corresponding number of Gamerscore points:

Big Bucks! (25 points): Earn those big bucks.
Dedication (80 points): Win every event in the DiRT Tour.
The Full Set (30 points): Drive every vehicle in the game.
Gut It Out! (10 points): Win a DiRT Tour event without winning a race.
Head Over Wheels (10 points): Roll your vehicle and still win the race.
Gnarly! (15 points): Finish with Flair! Cross the finish line with no more than two wheels touching the ground.
Keep It Clean! (20 points): Win a DiRT Tour race without crashing.
Terminated! (15 points): Take terminal damage while travelling at over 140mph (225km/h).
Nailed an Event (10 points): Win an event.
You're The Best, Around! (20 points): Win a race at every track in the game (in any game mode).
Dominated! (15 points): Win a domination event, getting the maximum available points.
That All You Got? (15 points): Win a Timed Throwdown.
On The Bubble (15 points): Be second to last at each elimination point but go on to win a Last Man Standing race.
Gate Crashed! (10 points): Hit every gate in a Gatecrasher event.
Friends For Life (10 points): Become true friends with a superstar.
Aren't You Popular! (15 points): Become true friends with 4 superstars.
Best Friends Forever! (30 points): Become true friends with every superstar.
Rookie Coming Through! (10 points): Race in your first DiRT Tour race.
Pro (15 points): Win a Pro division event.
All-Star (25 points): Win an All-Star division event.
Piece Of Cake (10 points): Win a Throwdown.
I like a Challenge (20 points): Win 12 Throwdowns.
Getting A Reputation (15 points): Reach Level 15 in the DiRT Tour.
As Good As It Gets (30 points): Reach Level 30 in the DiRT Tour.
Whose Backyard? (15 points): Beat Travis Pastrana in a Throwdown.
Block Party (15 points): Beat Ken Block in a Throwdown.
Jet Setter (15 points): Compete in a race in every location.
World Tour Winner (50 points): Win all the World Tour events.
X Games Champ! (50 points): Win all the X Games events.
Five Of Your Best (15 points): Win 5 Pro Tour races over Xbox LIVE.
Tourney (20 points): Take part in four tournaments.
Famous (20 points): Reach Online Fame Level 15.
Notorious (40 points): Reach Online Fame Level 30.
Rush Hour (10 points): Win an Xbox LIVE Pro Tour race against 7 competitors.
Mix It Up! (15 points): Play in every discipline over Xbox LIVE (Pro Tour or Jam Session).
In His Footsteps (25 points): Win 25 Rally races in the DiRT Tour.
With Great Honor (15 points): Achieve a 'Cautious' impact rating in Multiplayer races (Pro Tour or Jam Session).
Mirra Image (15 points): Beat Dave Mirra in a Throwdown.
I Ain't Afraid Of No Ghost! (10 points): Choose a ghost, download and beat it!
Dialled In (5 points): Win a race using a custom vehicle setup.
Two Cups One Girl (10 points): Win two team events with the same female team-mate.
X Games Europe Champ (20 points): Win X Games Europe.
X Games Asia Champ (25 points): Win X Games Asia.
X Games America Champ (30 points): Win X Games America.
Showboating (20 points): Bask in your success at X Games America.
Additionally, there are two secret achievements:

Just Drive! (15 points): You drove 100 miles (161 kilometres) without unlocking any other achievement.
For Colin (75 points): You've won the Colin McRae Challenge Event.