Bump for an indeed long overdue thread! I'm the guy with P7s and Yoko ES100s on the way, whenever those ES100s decide to show up at the Tirerack. From the sound of things I'll have no trouble, but I'll post here after thorough testing.
Todd Stratton out of Colorado has had some informative posts on wagon suspensions and just got Prodrive springs recently, and I believe he'll be running 225/45s once winter is over. One more potential source anyway.
Luke, what exact tires are the Tirerack guys running on their SSR rims? And are their wagons lowered?