Although this is a bad example of the speed tech I have discovered, at least is an example. With optimisation you can use this 'wallbang' technique to jump through the checkpoint, and as the wallbang is done it a right angle the car moves right, going through the checkpoint and landing at full speed. But better yet, you can use this wall bang on the jagged edges of the final part of the track to make a big skip. I believe with time I can accomplish this.