In icy conditions, chains or studded tires (not as practical) offer control that no tire can. Rubber doesn't grip very well on ice, 2WD or 4WD is pretty much insignificant at that point. Fresh snow ususally you won't have problems unless it gets packed down hard. On my old Toys, the few times I put my chains on, I'd put my chains on the front, because I wanted to be able to steer better. The other day, I went into the garage and put my old chains on the front of my 4th gen to see if they'd fit, and found out that there are major clearance issues with the front suspension components (UCA?). Seriously, I couldn't even pass my finger between the inside of the tire and the UCA component so I guess it'll be chains on the rear for now on, if necessary.