Changing to the 280 requires a new rear wheel (18") and the tire. Chopper City, Mtn Boss Hoss and several other BH dealers market wheels and the tires run about $300+. Wheels run about $1000+ each.
If you go to the Metzler 280, be consistant in checking and maintaining proper tire pressure. They do give you a bit better traction than the 230 (not much, but some).
Tim