Update 5:
Changes:

Doppler effects added.
Reworked engine sounds
Changes in rider physics so you can parry waves better. Use your throttle to parry.
Smoother landings after big jumps.
Balance changes in championships, a bit more challenging, a bit more fun
Bugs, bugs, bugs squashed, killed and burned.


What Santa added:

AI:s are enabled in split-screen multiplay so you and your family can enjoy some competitions in style.
And he mumbled something about hats....