Sprung for some dedicated wheels for the snow tires to avoid dealing with getting the tires remounted twice a year. Discount Tires Direct had the $100 rebate promo with their Ebay store so the wheels ended up being less than $100/each shipped.
After getting them mounted at the local tire shop, I went to Autozone to see if they had any lug nuts I could get to complement the new wheels. They looked him some for me and said they were M14x1.50 (which is incorrect; although I did not know that at the time). I brought them back and started the process of swapping them out. They didn't turn freely after the first 2 threads, so instead of stopping, I broke out the tools. Short story, I managed to strip two of my wheel studs before I realized something wasn't right - doh.
Went to the dealership the next day to buy 2 new wheel studs (Subaru calls them axle bolts officially). This was my first time replacing them on an outback. I was really surprised how much a pain it was to get the brake caliper mounting bolts off. Good lord, I don't think I could've done it without the rattle gun and socket extensions. Because this particular issue was on my front passenger hub, I couldn't lean on a breaker bar to free them (wrong rotational direction). I must've spent 20 min trying to break it free with hand tools. The manual suggests that they're torqued on at 88.5 ft-lbs. Couple that with road grime/corrosion and you've got two nasty bolts. The upper mounting bolt I got free with the impact gun and an extension. The lower mounting bolt, I couldn't get a good seat on it with a socket. Instead I used a wrench that was being pushed up by my floor jack. It made a nice loud pop once the bolt broke free.
After freeing those with the impact gun (good luck to those without pneumatics) hammering out the old busted up studs wasn't hard. Some PB Blaster to loosen things up and then a few whacks with my mini sledge freed it all up. This was my first time pulling (as opposed to hydraulically pressing)new studs in. Found this trick online. Buy a stack of washers to act as a spacer between the rotor and the lug nut (I used 7 M12 washers), press fit the wheel stud in the rotor and hub, stack your washers, and then finally throw on a lug nut. I started tightening it with a hand ratchet but moved over to the impact gun shortly. It seated everything quite nicely.
So that others may learn from my mistake, the correct lug nut size for the Gen 4 outbacks is M12x1.25
New wheel studs were $3.19 from my local dealer and a new lug nut was $3.89.
Wheels are the Konig Backbones 17x7.5