Here is the full list of all 14 Rock 'N Racing Off Road DX achievements worth 1,000 gamerscore.
Win the North America Cup
Win the Europe Cup
Win the Asia Cup
Win the Africa Cup
Win the Sourth America Cup
Finish time trial in 0:45 minutes or less
Finish time trial in 1:05 minutes or less
Finish time trial in 1:10 minutes or less
Finish time trial in 1:30 minutes or less
Finish time trial in 1:26 minutes or less
Finish time trial in 1:35 minutes or less
Drift for 4 Seconds