The Storm Island Add-on for Forza Horizon 2 has 23 achievements worth 500 gamerscore.
Complete every Storm Island Championship.
Win every Gauntlet Event.
Collect every Storm Island Bonus Board.
Win an event in the MG Metro R4.
Find and restore a Barn Find on Storm Island.
Complete every Storm Island Bucket List Challenge.
Complete your first Storm Island Bucket List Challenge.
Win the Storm Island Finale.
Drive every Road on Storm Island.
Win an event in the Ford Ranger.
Win an event in the '81 Ford Fiesta.
Win an Event in the Mitsubishi Galant.
Bank a Skill Chain of 100,000 points on Storm Island.
Win 5 Storm Island Championships.
Win an Event in the Robby Gordon #7 SST.
Complete your first Gauntlet Event.
Win 5 events in stormy conditions.
Start a race with Off-Road tires, suspension, and transmission on Storm Island.
Win your first Storm Island Championship.
Arrive on Storm Island.
Complete every Co-op Storm Island Bucket List Challenge.
Complete 50 Online Events on Storm Island.
Visit the Storm Island Car Meet and win 3 Showdowns.