Yow! I assume you are talking normally aspirated for both? This is the biggest model break in the history of the line. There are lots of differences, but here are the ones I can think of offhand:
Interior: F has six individual seats, like a 206. G has bench seat for middle row. Non-P G model still has six seats, but P model has only five. Non-P model has baggage door, P model does not.
F has conventional Cessna door, like 206. G has air stair door, even on non-P.
Gear actuated with electrohydralic power pak in G, F is engine driven pump on one engine (or optionally two pumps, one on each).
Front exhaust is different.
Pitot tube mounted inside left wing strut.
Fuel system: F: Aux and main tanks, see
www.skymasterus.com for excellent article on this fuel system. G: all tanks in each wing interconnected, so fuel is either on, off or crossfeed.
Fuel guages are float in F, capacitance in G.
Wing tip lights are flush.
Empty weight on F is lower than G by non-trivial amount. G has structure in it (like the airstair door) that is common with P model, but not really needed.
I think the aluminum wiring started in the G, but I am hazy on this.
There was an AD on F and earlier models to remove the soundproofing in the cabin. The material used was causing corrosion. Please check to make sure I have this one right as well.
I think the alternator warning system changed to idiot lights between the F and G models.
I think there are lots of other differences, but I probably got most of the major ones.
Anybody have some more to add?
Kevin