Well johngurley I can tell you there are some sharp guys here on this forum,(and KK40384 is one of 'em), that can offer technical and bargaining expertise that will probably help you with your decision.
I'm going to approach it from a different angle. A "buying used" tactical approach.
Its risk management. $6k beats $15k any day but whats the risk, and whats your edge.
Your asking questions, good questions, and in the right place, but all the answers are subjective 'cause the guys cant see the machine- and theres a 147 hr blank spot in this equation. This could be a great deal,and this could fail within 10 hrs. If you dont have records, and you cant see inside the powerplant, take a long hard look at what you can see.
Because in all my years in buying used I've learned you can take the current owners words and throw 'em out the window if he cant back 'em up.
Let the RXT talk to you.
You are aware that this pwc is a BEAST and the person that put 147 hrs on it in what? 2-3 years wasn't driving Miss Daisy right? No, Hell No.
Lets start at the bow. How does it look? Any impact evidence? How does the gel coat look below? Was it kept off the beach or was the shore used to stop momentum? Follow the bumper strip all the way around the unit. What's it look like? Were dock bumpers used or was the dock the bumper? Pull the seats. Hows the bilge look? How does it smell? Look at the battery and the area below it. Any acid evidence? Take a peek up the grate with a flashlight and check out the shaft,boot,wear ring and impeller. That's is a good one. If the owner starts to get defensive because your challenging his credibility, you probably have good reason to.
Maybe this is your first pwc, maybe not. Do you come from a boating family and you've already looked into all these suggestions? We dont know.
But if $6000 is ALL you got, be on your toes...Understand what the costs are at your local shop to do the things the guys are recomending. You might not take a hit, but you just might