What is the best single engine prop plane out there as far as best detail and most realistic features for FS9.
Pay, you have to ask others.
My opinion, in this order.
Maule, free. 6th down.
De Havilland Chipmunk -free.
if you're into something a bit trickier to fly...
try the Spitfire The detail on the panels is just amazing and beats the pants off a lot of other Virtual Cockpits I have seen from free add ons or in game aircraft.
They also have some other single engine aircraft that might interest you and if the quality of the Spit is anything to go by...
Its not free but the detail is amazing... my sig is from a screenshot of when i was flying it