Only one race car has been added for the time being, mainly to refine a racing system.
You can use an oak_boat to craft a race car.
You can use the caps lock key to drift, left ctrl to use N2O, and spacebar for small N2O.
Use the arrow keys on the small keyboard to steer the car.
And there is a built-in test track you can use (/place template qqspeed:old_street) to test the car!
Future plans: add more racing cars with different characteristics, customize racing models, provide api as lib.