I've added a couple of extensions to the track:
  • -A wall ramp so exiting the first U-Turn is easier.
  • -A ramp in the lava bridge.
  • -Made a couple ramps smoother
  •  -Added a seesaw track.
  • -More walls (the gray walls that destroy your car).
  • -A double wall ramp junction (as seen in the screenshot)
Enjoy the new extensions! I'll be adding more.