$16,900 was the cheapest quote I found for a NEW TC33D w/7308 loader, engine block heater, and filled R4 tires (I ended up talking a local dealer down to 17,500 instead). So you could look at your quote as trading 450 hours (plus whatever warranty is already used up) plus the filled tires for SuperSteer and a 72" mower. For me, I guess what would swing your deal depends on how much you really want/need the supersteer. It's an expensive option to pay for if you don't really need it.