If you want the BEST dedicated winter tire for a 4x4 SUV, the Bridgestone Winter Dueler DM-Z2 is your choice. They are more expensive than other winter tires because they work better than other winter tires. I'd recommend the 265/75R16 size for a stock 4Runner. I think it's nice to have a 2nd set of rims to mount winter tires on. With those and all Blizzaks, typically only the first half of the tread is the special porous rubber that makes it grip so well. So try to only use them during the winter when they're really needed. After 1/2 of the tread is gone, it's only a decent snow tire tread design - not porous sipped rubber for sticking to ice.

I haven't owned those tires, but I have experience from seeing them do well and talking to people who own them and love them. One of my co-workers last winter commuted from 10,000 feet down to Denver every day, usually with some snow/ice along the way. They used those tires and just loved them.

I bought some cheapo Firestone Winter tires ($50 each) just for the purpose of ice racing in a different class with my 4Runner 2 years ago. The Firestones very definitely don't grip ice as well as Blizzaks do, but they do grip a little better than BFG all-terrains. I bought some used 16x7 stock aluminum wheels from a Tundra so I could keep the tires mounted and available whenever I wanted to switch to those. Tacoma 16" aluminum wheels would work too, but the Tundra/Taco wheels have a larger center plastic cap that looks a little screwy with the front 4Runner hubs. So 4Runner wheels do look better on a 4Runner.

17" wheels will likely be more expensive, plus probably smaller selection of tires available. There aren't many winter tires in large sizes. Any tires for 17's will probably also be a little more expensive compared to 16's. I can think of a few negligible advantages of a larger wheel, but most people just want the look of larger wheels or a certain aftermarket wheel or maybe a certain tire size that you can get on a 17" wheel. Larger wheels probably are heavier and have more rotational mass since it moves more metal further away from the center, so it'll slightly slow acceleration and braking. Less sidewall on a tire means more accurate cornering and a firmer ride.