I bought my '03 WRX from Livermore Subaru, but that was before they moved locations (you can now see them from 580). I was going to purchase from Santa Cruz but the only Blue WRX they had was their Demo Car & I didn't want to purchase a Demo Car. I was happy with my experience back then.
Livermore Subaru also let me test drive the '07 Legacy Spec B, but I haven't Test Driven any STI's as of yet.
Good Luck with the car shopping.