Full list of all 49 DiRT Showdown achievements worth 1,000 gamerscore. It takes around 25-30 hours to unlock all of the achievements on Xbox 360.
You fully upgraded a vehicle
You came 1st in a Smash Hunter event
You achieved a podium in the Pro final
You wrecked your first opponent in Rampage
You survived for 2 minutes or more in Hard Target
You completed a Race-Off, Rampage and Head 2 Head event
You pulled off an Insane T-Bone
You got the First Blood bonus
You completed your first Showdown Tour event
Complete a clean run in a Head 2 Head event
Complete a Splitscreen event
Be in 1st place during each elimination period in an Eliminator event
View a Crashback replay
Send a Challenge to a friend
Dominate all sectors during the final lap in a round of a Domination event
Be in last place and then earn a podium during double points in a Rampage event in the Showdown Tour
Complete a Showdown Tour event in each location
Own 15 vehicles
Win a Race-Off event without boosting
Use a full tank of boost in one go without crashing in a Race-Off event
Achieve a podium in the AllStar final
Achieve a podium in the Champion final
Win an Online team event
Collect all 100 Hidden Packages in Joyride
Wreck 20 vehicles in the Lafayette Eulogy
Accept and beat a friend's Challenge
Complete the Showdown Tour with at least a Bronze in every event
Own every vehicle in the game
Complete 50% of the Yokohama Compound Missions
Achieve all hit types in Rampage
Complete 50% of the Battersea Compound Missions
Hold the loot for 2 minutes in Smash & Grab
Score 300,000 points in a Trick Rush event in the Showdown Tour
Complete the Donut King Mission in the Yokohama Construction Site area
Earn a total of $1,000,000
Drop the Flag off 5 times in a round of Transporter
Complete the Showdown Tour with at least a Silver in every event
Reach Fanbase Level 30 Online
Reach Fanbase Level 10 Online
Achieve a 5x Wrecking Streak in Rampage
Win a Speed Skirmish event
Complete 100% of the Battersea Compound Missions
Complete 100% of the Yokohama Compound Missions
Achieve a podium in the Legend final
Dominate a friend in Challenge mode
Complete all Joyride Missions in both locations
Fully upgrade all vehicles
Reach Fanbase Level 20 Online
Complete the Showdown Tour and win Gold in every event