The Looney Tunes Expansion Add-on for Hot Wheels Unleashed has 3 achievements worth 45 gamerscore.
Win a Quick Race on a track in the Looney Tunes Adventure Park (not unlockable in Split Screen).
Upgrade the Rarity of a common vehicle of the HOT WHEELS™ - Looney Tunes Expansion.
Complete the Unleashed Goal of an Event of the HOT WHEELS™ - Looney Tunes Expansion.