yes i do........
there is always room for improvement the designers who build those motors im sure have taken them alott further up in the power range with there R&D motors,however it does take years,and deep pockets,and a wealth of knowlage,and boat load of theory, not saying you cant bump a couple hp's you have time and power heads, good technical advice, there is no reason you shouldnt be able to bump the power on one,, you might go thru 10 power heads finding the right setup, dont expect to beat your buddys by taking a die grinder to your power head first try,,,, it could take years and more $$$$ than you want to admitt,, to end up with a turd 90% of the time..
i'v never modded an outboard ,, but i have a 500 indy that will beat any stock 500 indy in 100m.,,,,corner to corner.....it took me 4 motors to get this far,, i have another block with a different ports cut, (closer to stock then the last one,) and i want to try cutting the pistons, when this one pops,,, its been together 3 years now... i think i have around $5000 into this $500 sled, and it is a turd,,, first 3 motors were slower than stock,, by far..now its a little faster than stock 10 years later, way to late for the races lol
and i wouldn't dream about touching a newer sled/outboard, to try and mod,, you absolutely need to pay someone for the new technology,,, do it yourselfers cant keep up