I don't recall if this is a single or two-step hull. Mine is two-step and quite heavy. With an H-O, stock 24p B-1 prop, turbulators out and full-synthetics I can hit 68 on a decent day trimmed up on the back step. I have a 22p for real-heavy, real-hot days. A 26p would be pretty useless on boats of this weight with this power. Headers, synthetics, and an ECM re-tune would swing a 26p quite well - but you would be getting away from 87 octane.
In the real-world, on a 110 degree Havasu day, 4-6 adults, three ice chests, and full tanks; it's a solid 60mph boat. 4000 gives me around a 42mph cruise, which I am real happy with for a fully loaded cruiser of 30-feet. I see no reason for it to be any faster, as all of my passengers (one being the wife) don't ever want to go over 45 anyway. The only time I get to air it out onto the steps is on super-calm water or by myself. So, personally, I don't need a 75mph boat as I only rarely get to see the top speed I have now.
I pay right at $800/year for insurance with no lay-up.