Try to find who has been maintaining the MTUs. Find all records. Any extended warranty's still on? Any available? Was there a captain? Contact him. People have a love / hate relationship with MTUs. They love them when they run well, hate to pull out the checkbook when they don't. Finding a good MTU shop is hard also. If your looking at this type of setup, You may already have an idea that this type of boat and equipment is high maintenance. Time to find your new best friend, A real MTU guy.
So, after all the bad ribs and thoughts, What did you decide and why? It's an inquiring mind thing....
I know the boat you're talking about. Be very, very careful as nothing was done to the boat to prepare the engines for the three + years that she wasn't used. Have an Mtu mechanic remove the injectors and lubricate the cylinders then prelube the motors with an external oil pump before you try to turn those motors. If you can't do that at the very least have someone borescope the motors to see how much corrosion there is inside.