This is considered a Summer Car.
If used during a Summer Event, you get 25% extra cash and XP from races (50% before the 2018 Surf n' Turf Event).
The Six Four is a car that could be obtained by completing the achievement Surf's Up!, which required racing 400 times with a summer car during the 2015 Summer Event, or by completing the achievement Surf's Up by using 1,000 nitros with a summer car during the the 2018 Surf n' Turf Event.
- The Surf's Up! achievement that originally rewarded this car is a different achievement than the congruently named achievement that awarded the Hang Ten for 400 races with a summer car in the Summer Events of 2013 and 2014.
- "Surf's Up!" and "Surf's Up" are two different achievement that both rewarded this car during two summer events.