Need for Speed Unbound

All Tier-Class trophies can be boosted with a friend in a Party! Go to the Multiplayer Mode, invite a friend to the Party. In the Open world, Drive to the Tier you want (B - S+) and when you set up a Race, Just invite the Party! (Not all Others in the Lobby) Finish the 3 races and the Winner will get the trophy! You don't even have to buy or own Cars of the Tiers, you can rent them.