I'm in Wisconsin and my parents house has tyvek on one addition, after about 20 years they put another layer on because it has some odd angles to side over that no one wants to do.
I like tyvek not because it acts to seal the house from air but because it helps seal the plywood sheathing from water, for air sealing I would rather caulk as well or use the expanding foam, or they even make an expanding construction adhesive that you can get for the gun foam guns, but also vapor barrier should be on the inside in most houses, not on the outside, that is why tyvek is used on the outside, it breaths.
They don't at any point that I saw say how they get fresh air in to the house, I suspect that the bath fans are the style that have heat exchangers built in to them (Panasonic makes a few like that bring in preheated make up air) but the trouble is the tiny heat exchangers in those bath fans freeze up easily so there is a bypass flap that closes off the heat exchanger at 20F.
The advantage of a house like that over building a 2x6 wall is that 2x4's are cheaper, last I looked they were 40% cheaper so even tho you use twice as many your cost only goes up by about 20%, most building inspectors should also be ok with that style of framing because it's basically a 2nd wall on the outside of the house.
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