Ya the directional angle adjustment is to reduce drag. This one is hot pink though. Has to do with reducing drag and increasing hydrodynamic cavitation. Said if I wax the "hole" it will add another 2-3mph. Should be neck and neck with the cigar boats.

May add a flowmaster 40 series for a little extra rumble

It's a shame you don't have the table and seat benches to go with it. Mounted before the drives dramatically aerates water for props and screens out seaweed. It's not un-heard of for a big power bayliner to pick up 28-32mph with that setup.

Pink umbrella like this one?