winter storage (as in Canadian winter)

McFly

I went for my first test drive yesterday in a '13 sport coupe - love the feel of this car!! (not to mention the look! those vertical LED's on the bumpers are a nice addition IMO)

anyways, I asked about winter storage, he claims simply disconnecting the battery and covering for the winter is good enough. We can hit -30 to -40 C for weeks depending what part of the country you're in, do you all agree this would be suitable for such conditions? I've heard of people draining certain fluids when storing for the winter, would that be necessary?

I was also told that undercoating would be a good idea as well, does that make sense?

thx folks!