I finally got some new rims - 18" XXR 530s Matte Black offset +33 and 8.75" wide paired with 245/45 Potenza RE760 Sport. I love them. The 245/45 are fat and fit the wheel width pretty well. I was looking for a flush fitment from the new wheels, and they seem to poke just a hair. The rear fender is cutting away the tire after a road trip with a heavy load, even though I have the original Outback suspension, which is a huge disappointment. I'm buying a fender roller kit for $60 on amazon, which is cheaper than the local shop... $80 for just that back 2 wheels!
UNFORTUNATELY... the new wheels shake at highway speeds. I had them rebalanced twice at two different Pep Boys and a third time at Firestone. No one could fix it.
I bought hubcentric rings, have the conical/tuner lugnuts for the XXRs, placed the wheels on carefully using the star pattern for the lugnuts. I have new front bearings and axles.
After I rotated the front wheels to the rear, the shaking moved from the steering wheel to the rear of the car, so I know it has something to do with the wheels.
I called the distributor of the wheels (NLMotoring.com) and they said to get a road force balance, which I've never heard of but it seems like the next best idea... which is a wheel balance that simulates driving. Hopefully that fixes it
Here are the before and after pictures, the image of the original wheels were taken with a DSLR, the other is with an iPhone :/