Sorry to dance around a straight forward recommendation. I was trying to guide you into determining your pump's condition and making your own decisions without me degrading someone else's work.
While I was at B1 Racing, we just replaced them with a stainless wear ring from either American Turbine or Place Diverter, wether they needed it or not. None of us were confident in a urethane part that is in continuous contact with the rotating impeller, nor are we confident in something that is intended to "fit" or "clearance" itself during operation. We have installed a lot of bronze wear rings and have experimented with some plastics. The problem is, soft materials wear quickly, the clearance opens up, and performance degrades. For this reason, a stainless wear ring and stainless impeller work best for us, but you absolutely can not run them out of water.
I don't know the secret to making a UWR work. I honestly don't see myself going through that learning curve either. If you want to use that UWR, I would call Dwayne and ask for his recommendation.
I will offer a few more thoughts:
1.) I could go along with two people who said, "just run it." I say that because it isn't a big deal for me to pull my pump apart for inspection. If that really isn't an option for you, I would make sure that it is right before installing it. That would give you the best opportunity at a "set it and forgot it" scenario. I will assume that you would keep up on maintenance, however pump maintenance is neglected by almost everyone.
2.) Without actually feeling the resistance that you are feeling, nobody can tell you if it is too tight or not. It is a good sign if you don't feel any binding points, meaning the resistance is constant through each revolution. If the pump has been run previously, the UWR shouldn't still be overly tight. BTW, I would not run an UWR out of the water.
3.) I am of the opinion that if you don't have a warranty and someone who will take care of you when you have a problem, I would like to know my boat intimately. Having said knowledge, you will know what pitfalls you can expect, and have the knowledge to resolve issues as they arise. Jet pumps are very reliable (even when ignored) and are easy to maintain. If there is an underlying problem, its best to catch that right away.
4.) The damage that you really want to avoid is:
A.) Contact between the impeller and suction housing.
B.) Anything that could cause the wear ring to weld itself to the impeller, spinning it, and destroying the suction housing wear ring bore.
C.) Thrust bearing failure. A thrust bearing failure will destroy both your impeller and suction housing as well as destroying your engine.
D.) Lack of lubrication to the bowl bushings. The shaft will literally wear entirely through the bushings and destroy the bushing bore in the bowl.
The big dollar items are the suction housing, impeller, and bowl. Nothing else is really cheap. I'm sure you can appreciate the necessity of protecting your big dollar investment.
