Sternone
There was a predictable rise in oil consumption and dropping compression readings during as little as 300 hours of operation. Fortunately, these excessive wear indicators did not lead to any catastrophic failures. But many owners discovered that a quarter of the way to overhaul, top-end engine work was necessary.
Is this still an issue with the M20M? 300 hundred hours and major work being required is not good on a turbo Mooney. My mate has had no such problems with his turbo Cirrus.