The M90 Eaton Supercharger works well. Here is a vid of my plastic boat, got my wife to drive while I filmed it!
http://www.youtube.com/watch?v=ybPMybu0tIUTHe blower transforms the Lexus V8 and makes up for the lack of cubes at lower RPM. Not sure how the cyntrifugal blower will go for pulling fat bastards out of the water - where you need power most!
I'm getting 60mph it's centermount and no cav plates - just the small one above the rudder. Engine is stock and running about 7psi. With the cowl down you can't hear the blower except at WOT which is excellent for social skiing.
I have the bigger Eaton M112 off a supercharged Jag V12 to go on it next.
Haven't looked for a while, but the eaton blowers are cheap secondhand under $600 for the M90 and about $800 for the bigger M112
Cheers, Andrew