I always find that local people give better deals than online sales.
if someone has taken the time to take pics and post on ebay or nasioc or something like that, they tend to want a good price, also cuz they have to go through the hassle of shipping.
But people local to you who modified their cars and have stock parts sitting on a shelf in the garage and are too lazy to post them for sale, typically make really great deals, especially if you are standing their with cash. I go to my local subaru meets, and participate on my local subaru club (I live in maine, so all the subaru enthusiasts around me connect on mainelysubarus.com) When I notice that someone is talking about thier new fancy uppipe or turbo on their STI, I ask "what did you do with your stock one? I'll buy it from you" and usually that has been enough to make great deals.
that being said, I no longer have my forester. put it back to stock and sold it a year ago.