Back in the 80's many 'boat test',"Black" I/O engines had major work done on the insides of them.(and painted over) The magazines played stupid, and just kept raking in the advertizing $$$$'s. Some of us got tired of the "purchased praises", and just never returned for the "tests". Prior to GPS, speedo water pick ups and dash units were "tuned up", often we went to tests thinking we were behind in our own tested speeds, only to find out that we were one of the fastest. After a few of the "worlds fastest boats" fell behind in top speed tests, the rules went out the window. Then the motors got bigger and bigger, will it ever end? I hope so! Stock motor packages, are the best way to go! Then you can compare hull speeds and control, loading, and water conditions. We all know that a 572"/ 1471 blown boat/brick will make anyone happy for the 'test week', but what about the OVERALL COSTS and maintainance, of owning that boat? Should that boat be included in the 'Family bowrider' section of the tests? Stock motors (packages)will help level the playing field.
The magazines should use a prop shaft mounted dyno and measure the real output before they even put the boat in the water. That plus GPS eliminates all of that BS you mentioned.