Oh just to revisit this...so I bought a 2013 STi in January. Haven't tracked it yet because I've been researching what is needed to turn it into a track car. And I'm finished with my research and happy to report it needs absolutely nothing. Nada...zilch. A lot of guys just run them stock at the track and they are perfectly suited. Brembo brakes, tight suspension, factory 200 treadwear tires, etc. Oh and retains the factory warranty and free maintenance. Perfect track car for someone like me that is mechanically inept.
Seems like the STi should work nicely at lower speed/tighter tracks like SOW and I can run the M3 at the fast tracks like Big Willow.