Has any of you guys tried this product before with noticible results??

WET FOLF Adjust-A-Thrust, Self Adjusting Pump Cone:

The Adjust-A-Thrust is simple to install and easy to tune.
Installation on most models takes less than an hour. Initial tuning takes half an hour at your favorite lake. The Adjust-A-Thrust constantly shifts back and forth, changing the size of the pumps exit nozzle automatically. For maximum low end, the center shuttle is retracted, opening up the nozzle and allowing a large volume of water to be moved to accelerate the craft. As craft speed and pump pressure build, the tapered center shuttle is forced out into the exit nozzle, reducing its size and increasing water velocity, which increases top speed. Letting off the gas lets the shuttle backshift into low gear. The Adjust-A-Thrust is race legal in all classes except stock class. The Adjust-A-Thrust has been shown to affect top speed by as much as 3 mph. Typical gains are .5 to 1.5 more top end and better midrange.