stuart (h20) is right about the engine going on and on. we have put 300 hrs on hour this year and it hasn't missed a beat.
You need to check the Hours on the engine,
You need to check the Service history and remaining warranty,
Ask if the lump has had it ECU replaced, this does sometimes happen and it's for the better , but if it happened you need to work out when as the engine hours would have been zeroed.
i would personally take it at my own expense to a service agent and get him to do a printout for me and ask his opinion of engine.
If the engine is good, and they usually are, then I would reduce the cost of the original engine by 20% for the first year and a further 15 for each year afterwards. That will give you the value of the engine. In my world this values the engine at 5.5 k max
If after that the Hull and trailer and other stuff is saying to you I am a bargain at 8.5 k then you are in the Zone.
BWM are Ok boats , not the finest examples of Ribs out there but they are OK. I must admit though that Jahno is flogging a new adventurer for this Kind of money and it looks a much better deal.
You could also Buy a very decent prosport for that kind of money
I need a little bit of Rhythym and a little bit of Blues