I talked to a friend of mine who used to build and race PowerPlay go-fast boats before I bought my overpowered V-20. He said if the transom will handle the push of the engines, the hull will handle the speed, though it could get squirrley at high speed with some waves since it is so short. Also, for a given speed, an increase in hp does not equal the same increase in speed. He said 70mph is elusive and for some reason it takes gobs of power for any boat to get there and even more gobs to break 80 and nearly double the hp from 80 to break 90. The Scarab 22 with the stock 330hp BBC runs upper 60's, but the same boat 502/502 Mercruiser will run upper 70's 180hp for 10mph. Eliminator makes a 22' steplift hull and they will give it to you with the 502/502 Merc. Point is, is if you pay attention, it's not quite as lethal as one might think. Just build the transom right and forget about insuring the thing. I don't know about other states, but you can get a boat recommissioned as home built here in Texas to keep it legal.