I didn't do
anything other than General Altimax Arctic studded snows on my OEM wheels. Already have flaps. No special undercoat or paint sealant or anything. Been under my car dozens of times since last winter and it all still looks new, (except the stock exhaust I guess).
Drifts like a champ, especially with the 22mm F&R sway combo. the open diffs don't seem to spoil the fun either, all four seem to spin just fine.
Drift night is a dangerous endeavor, but you can generally find your own space to hoon about in, and to be honest, the empty roads mid-storm are a lot more fun than any parking lot.