The Mud and Guts Car Pack Add-on for DiRT 3 has 4 trophies - 3 bronze and 1 silver.
Drive all of the cars from the Mud and Guts Car Pack
Win 5 online races using cars from the Mud and Guts Car Pack (Pro Tour & Jam Session)
Complete a clean race with a car from the Mud and Guts Car Pack
Win a race at night using a car from the Mud and Guts Car Pack