The NASCAR Expansion Add-on for Forza Motorsport 6 has 16 achievements worth 210 gamerscore.
Race in a NASCAR multiplayer league
Finish the NASCAR Icons Tour Expedition
Complete 1 NASCAR Showcase Event
Finish your first NASCAR race
Drive 50 miles in Hendrick Motorsports NASCAR models
Drive 50 miles in Team Penske NASCAR models
Drive 50 miles in Stewart-Haas Racing NASCAR models
Drive 50 miles in Joe Gibbs Racing NASCAR models
Complete a lap of Homestead in under 30.5 seconds
Drive 50 miles in Chip Ganassi Racing NASCAR models
Race in a NASCAR multiplayer hopper
Finish the Passport to the World Expedition
Finish the One Lap of America Expedition
Finish The Road to Le Mans Expedition
Complete the full NASCAR World Tour
Complete all 10 NASCAR Showcase events