Hi Newlands,
You say four in your family so I assume that includes yourself.
I can see your logic wanting a six seater as most four seaters can't really carry four. As has been suggested the C182 is one of the few genuine four seaters around and there are plenty to choose from.
The RG models are a bit scarcer but about five knots faster. I have a reasonable few hours in both types and have found them hugely capable.
Cruise at 65% in the RG I've found to be 140kts TAS at FL75 at 50lph.
'98ish (fixed gear) onwards fuel injected, 135kts TAS 40lph.
There is usually around 1100lbs useful load and the later ones hold up to 330ltrs of usable fuel.
D.O.
Edited to say I agree with Achimha. The small wheels are a pain on the RG. They allow the brake calipers to drag in the grass.
Last edited by dont overfil; 24th February 2012 at 14:27.