Those are all over the lake of the ozarks. Neighbor had one for years from the original Miami factory. We have poker runs and top speed shoot outs on the lake all the time. Some well over 180mph. Unlimited hydroplanes and drag boats as well. No speed limit at the lake except at night. It is good fun and there is lots of money being spent.  1300 miles of shoreline. 

You can buy a two year old boat, same company, and go faster for half the money. Really bad investment when new. The most fun guage is the gallons per hour one. There is one for each motor. You can spend thousands on gas in one weekend.   Not exactly green but an effective Panty removal device. 

They are also known as compensators. If you don't see it take another look.