We bought a 2013 Impreza Premium with the 17 inch alloys a month ago. Drove it just long enough to be kinda disappointed with its crosswind stability before we headed off on a 4300 mile trip. Got back a few days ago and in 30 days I have put 5600 miles on it.
On the way home, we ran into some snow and serious ice which required 40mph speed on the interstate for 3 hours. I was dismayed that it also was unstable on snow and ice. I recalled that one of my checklist items before leaving for California I checked the tire pressures. So I called the dealership to make an appointment to have the alignment checked.
Well, today I ran across my "checklist" and found I had not checked off the tire pressure from a month ago. Cough. You guessed it. I checked and the pressures were way high - 38lbs, 36 lbs, 36 lbs and 34lbs. So I lowered them to the correct pressures. By coincidence I had to do an hour of interstate driving this afternoon and I'm happy to say the car is transformed. So this chassis seems inordinately sensitive to tire pressures - often an indicator that a lot of development went into the handling.
I called and cancelled my appointment with Subaru.
As a random comment, this evening I discovered something while coming home in the snow. If you use the parking brake to slide the tail around corners it shuts off the stability control completely until the brake handle is back down. So if you want to horse around, find the click point you can leave the handle where the brakes are not dragging and you can slide around to your heart's content without messing about pulling fuses, etc. FYI the dash switch does not turn off the traction control completely but this seems to.