Went to the local Circuit City (I've had all my other cars done there) but when I asked about getting new speakers for my WRX the guy said Subaru includes an amp "somewhere" in the car, and I'd have to have all new wiring. I'm not even looking at component speakers, just regular 2-way/3-way speakers.
He also said that the rear doors take 6 1/2" speakers, not the 4" speakers Crutchfeld says. Decided to go to Best Buy, just to see what they'd say... and I'm surprised he even know what a Subaru was.
I'm not very comfortable doing this myself, so I'd rather pay to have someone do it, but I feel like I'm being rail roaded.