Change of MTOW over time
 

Out of curiosity, what changed from the first to the F model to enable such a substantial extension of MTOW? I haven't come across anything describing aero-dynamic or wing changes, and they are all rated at 210 HP continuous. Perhaps I missed something in my reading.

changes
 

From what I have seen in my minimal research:
1. Elevator travels (see the TCDS)
2. Noticed that 337-0526 & on have additional doublers on the main landing gear bulkhead assembly (increasing strength in the lower part of the bulkhead)

There are likely a few other small ones, but spending some time with a Parts Manual will likely net you a great deal of results.

Of course, as the MTOW increases, the performance decreases given that the horsepower and airframe do not change.

Jeff