"The boat is rated to 2600 rpm and it will pull that in neutral at the dock with no smoke"
Your need to be able to reach more like 2750 in neutral as a brief high idle test.
-Are you sure your tachs are accurate before taking too many readings?
-Do you have EGT or boost readings?
-Can you confirm the turbo's operation and their output?
-Could there be blockages in the air side or on the exhaust side from 'sitting'?
- Do you have known functioning trim tabs?
- Can you move weight forward to see if that helps?
1997 was a prime year for Bayliner and others to overprop their boats as one way to achieve bragging rights in brochures and at boat shows. I think you will find a host folks with similar boats that may have ideas on this at the Bayliner site - baylinerownersclub(dot)org
Bayliner Owners Club - BOC Forum - Category Index
If you post in the motoryachts section I will be surprised if you do not eventually get feedback on that same boat with the same engines.
It would be very beneficial if you had the trans ratios on your boat handy (port and stb) as well as the details on your props (D X P X blades and materials).
Lacking any other detail but reading 1,000's of posts over at the Bayliners club over the years my best guess is that you are overloading the engines and the props are well over their desired pitch.