Turning a little harder to the right under power is normal due to the prop rotation, just like pulling to port in reverse. If it's really hard it could be a handful of things, from the rudder port to the helm to the cable... Is it easy to turn both ways at idle? Like, with one finger?
Have you checked base timing? Just a thought on the high speed issue, and a place to start that's free and fairly easy to check if you have a timing light.
Is the hose leaking from the sidewall or down the pipe that it connects to? Could you tighten up the hose clamps or add one where it leaks? If it's coming out the side of the hose, yeah it should be replaced at some point.
1989 Bravura - repowered with 2001 PCM 351 GT-40 - 1.23:1 PCM Trans.
1989 comp - sold
1985 comp - sold