I finally changed my spark plugs tonight at 42k miles. I love my WRX as much as anyone can love an inanimate object, and I love the beautiful EJ20 that comes in it. However, that flat four is a super pain in the ass to change spark plugs on. Everything went relatively smoothly, but it still took 2 hours. Sorry, I just had to rant a little. By the way, I went with the Iridium NGK one step colder (BKR7EIX-11) and they are awesome. I could tell a huge difference in response just in the few miles driving around tonight.