Unlock the Dynamite car by racking up 3,400 points in the World Tour Mode. Go to the California cup, select the San Francisco area and select the race track called "Rocky Road". The Dynamite has a small fuel tank and you'll run out of gas by the time you've nearly reached the finish line. Avoid the fuel pick ups and use your boosts whenever necessary as the Dynamite will easily speed past other cars (you can still boost even after you've run out of fuel). Make sure you never pick up any fuel or else you have to restart the race. Also, make sure you don't upgrade your fuel tank by way of the upgrade races. In my case, I never upgraded my fuel tank. You can also repeat this method, but stop before the finish line to earn the Trophy called "Call Roadside Assistance".