Just out of interest, do Yamaha know that you are copying their hull? I doubt that they're going to like the fact that you're stealing their IP (the hull shape) to make money.. just my 2c.
For your information andrew I am sponsored by Yamaha they help with parts , i run there stickers and promote there ski's, the point is yes there is alot of changes, apart from just the material, the pump intake is different, chines are different, the hole engine bay with firewall is custom.
We are making a new hood which is custom as well.
We all start out on stock superjets and Kawi's then we get to a point where they can not take the abuse and these hulls are required, if you have any questions andrew come to the yamah Freeride on the gold coast i am sure there are alot of 97-08 aftermarket hulls.
And everytime someone wants to get into the sport they go buy a stock yammy first that is what i tell everyone to do i have seen people buy after markets ski's and can not ride you need the basics first.....o and the aftermarket racing hull bottom will actually be on the yamaha display for the PWC expo in February 21 , u are welcome to come look and ask anything you want.
Cheers
Pete