Here is the full list of all 12 Yaris achievements worth 200 gamerscore. It takes around 5-6 hours to unlock all of the achievements on Xbox 360.
Complete a track having reached a speed of at least 250 mph.
Race all 8 tracks in one sitting and complete the final track with full shields.
Obtain all weapons at least once before exiting the game.
Complete a course in 3 minutes or less.
Complete all 8 courses in under 40 minutes. Only your best career times from each track are used.
Successfully finish track 4 by killing the Giant Spider boss.
Successfully finish track 8 by killing the City Transformer.
Finish track 8 in any multiplayer game and kill the City Transformer.
Save up to 1 million coins.
Collect 1000 coins.
Create or join a multiplayer ranked match and achieve the highest score.
Win or lose, finish a race with another player online.