The reason I am going with ballasted tires is that I have very hilly property. About the only ground engagingI've been running my tractor for twenty years with no ballast. Even plowing with it when the conditions are right. In fact, I was just thinking the other day about how much damage I could do if the tires grabbed any better than they do. I already spent over $5000 having one of the little planetary drive gears for the left side replaced. Unless the tractor is built very stout, I would not ballast the tires on the smaller utility tractors.
attachments I run are a middle buster, roto tiller, and box blade. Also, I regularly maxed out the FEL on my L3400 and brought the rear end off the ground even with a 3pt skidding winch on the back and ballasted tires. (Moving logs). The L3400 is only 2500lbs + 800 or so for the loader - the Kioti is 3400lbs + 1400 for the loader. What machine are you plowing with?
I guess I would rather risk breaking something on the tractor instead of my neck.