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.
Defeated the City Transformer in a multi-player game.
Defeated the City Transformer!
Completed a track having reached at least 250 mph.
Played a multiplayer game online.
Won a multiplayer ranked match!
Defeated the Giant Spider!
Obtained all weapons at least once.
Completed a course in under 3 minutes.
Collected 1000 coins.
Race all 8 tracks in one sitting and complete the final track with full shields.
Complete all 8 courses in under 40 minutes. Only your best career times from each track are used.
Save up to 1 million coins.