A Clutch Nixon stunt by the PIN-K0 Radar Station in Jacob's patch.
The main thing to focus on here is staying on track. The time limit is relatively forgiving, so you don't need to mash down the accelerator at all times- hitting a rock wall or taking a jump off-kilter is much more damaging to your chances than a carefully-taken turn. With the exception of the final banking sequence, try to keep yourself level at all times- everything else will flow from that.
If you do hit a wall hard, don't fight the spin, but try to make it a full 360. With any luck, you'll only lose a few seconds. Finish the course to complete the stunt, and unlock the Shining Sea jetski vehicle.