Lots of piston ring failures on the MY08 and 09 Subaru STI's. I personally would not get one until they get their "stuff" together.
Subaru has some problems right now + they dropped out of the WRC. Most everyone that I hear from likes their Subaru hatchback STI...until it blows a piston.
I also drive an '07 STI.
Check the topics on IWSTI.com
http://www.iwsti.com