An xr is in the $6-6500 area. When I called for scx price I was given $15-16k for everything. I didn't shop around so maybe there are better deals to be had. Like mentioned if you break a couple xr's you could have bought a scx setup.

I don't know anything about racing with skiers behind the boat, specially at 100mph.

SCX upper and SC lower. Worry free set up for that HP.

I would take a look at the weight differences on each. The SCX is much larger but seems like it could be too heavy on the back of an 800lb hull. I did a quick search but did not see the weight #s, Might be worth checking