Maybe I can help. Have owned two; first was a 1975 M20E Chapparal; 200HP, normally aspirated, fuel injected, owned for 10 years - wonderful!
Second (present) 1980 M20K 210HP Turbocharged, owned for last 7 years, even better.
Previously owned Cesna 177RG and Grumman Cheetah. Mooneys have been by far the best of all.
Used to plan on 150Kts at 38Lt/hr in the M20E Now plan on 170-180 Kts (depending on altitude) in the M20K, (42Lt/hr.)
Maintenance has been reasonable on both, - no nasty surprises, but I am the ONLY pilot and am very familiar with operating requirements.
The M20K, in particular, is a surprisingly versatile aircraft. It is capable of operating out of a friends 650m dirt strip but equally at home at FL180 on a 1000nm non-stop trip.
I'm in Australia and frequently fly Sydney to Mackay non-stop, 75% power, landing with more than one hours reserve.
Mooneys are fairly popular here in OZ, due to good speed and range capabilities.
Only downside is payload. M20E was a 4 (small) pax hauler with light luggage, the M20K is a 3 person machine at best.
Very active owners group with annual advanced training courses. in US and Australia.
If you have any more specific questions, let me know.