I have a WRX, and switched to Mobil 1 at the third change (9K miles). I use a graphite additive (Krex), and I still change every 3K miles though, since I often shift around 6K rpms, and even cruise at 3500 (mainly because 40mph is at a bad spot for 4th gear, and I have to drive that speed quite a bit). And if it matters, I take it to the redline almost daily. My dealer says that it may be detrimental to change synthetic that frequently. I read a lot of posts talking about how long you can go between changes, but none about whether you can change 'too' often. Seems like clean is clean no matter what, to me. I've been using 5W-30 in winter, and 10W-30 in summer, and have 27K miles on my car. I have upgraded to 287hp, and run a little rich on 93 octane. Coming up on 3K this week, so should I wait or not?