As far as a tractor flipping over from ballest in tires or from wheel weights while pulling a 3pt implement gonna be hard to do! The traction gained from weight over the rear wheels really a big difference in traction I can't blame you for wanting to try another tractor but if this is the only reason you are thinking of a 4wd try loading the rear tires and possibly wheel weights. I do have a 4wd Kubota also and I know I'm gonna open up a whole can of worms here but I really believe 4wd drive is over rated! Don't get me wrong it's nice! To have in certain situations for me especially like loader work I just put in a 80 ft extension on our drive way and dug out aprox. 4 to 6" of top soil to put stone in in 2wd tractor just spin but in 4wd and proper loader pressure dug in a cut beautifully worked real nice. And in very wet conditions I have used it. But 90% time my tractor is in 2WD even snow removal I have rear chains and my area is not super hilly so I under stand the need for 4wd on hills also! I'll be honest I love my Kubota 4wd but for what I do where I live if it weren't for resale value I probably would have bought a 2wd but around here trying to sell a small to medium tractor in 2wd is hard.now I don't plan on selling my Kubota but god forbid if something were to happen to me my wife and family can sell the Kubota really fast just because it's a Kubota and 4wd drive!