The Storm Island Add-on for Forza Horizon 2 has 23 achievements worth 500 gamerscore.
Complete every Storm Island Championship.
Win every Gauntlet Event.
Win the Storm Island Finale.
Collect every Storm Island Bonus Board.
Win an event in the '81 Ford Fiesta.
Win an event in the MG Metro R4.
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.
Win an Event in the Mitsubishi Galant.
Find and restore a Barn Find on Storm Island.
Bank a Skill Chain of 100,000 points on Storm Island.
Complete your first Storm Island Bucket List Challenge.
Drive every Road on Storm Island.
Start a race with Off-Road tires, suspension, and transmission on Storm Island.
Win your first Storm Island Championship.
Win an event in the Ford Ranger.
Arrive on Storm Island.
Complete every Storm Island Bucket List Challenge.
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.