I'm happy to see this one stay on target. I agree on the reduction....I'd try to feed and discharge at 100% pipe diameter without any fittings for at least 15" for best hope.
The pumps are going to cavitate....how much and how it affects the downstream piping will be dependent on how fast the pumps are ate up and how the actual flow ends up settling in.
Buying yourself 5-10 pipe diameters of straight run piping is your first line of defense. There may be opportunity to reduce the cavitation by changing pump rpm, introducing flow or suction stabilizers....etc.
I would not buy something that runs on any kind of primer given the possibility of primer shortages and even regulations. In fact, why not buy a flintlock? Really. Rocks aren't going away anytime soon.
