I nerfed the jump height for future downloads (but I'm not going to make another video). It's now more like something you'd use to get over an opponent in a race, or to jump up onto a platform or over a small gap, rather than something you'd use to rocket around a map and do flips with nothing but the force of the springs.
If you prefer the jump height which is represented in the video, change the force value of FreestyleBuggyJumpSpring to 30000. This datablock is defined in FreestyleBuggy_Jump.cs. That is the only difference.