Hi, long time reader, first time poster here! I'm an automotive noob, but I'm a pretty handy guy, and I want to personally care for my new baby: a 2004 WRX. So I want some lube advice if you guys would be so kind! Engine: I plan on going to Mobile 1 5w-30 within a couple hundred miles. It's got 1100 miles and factory oil in there currently. I plan to do so without a flush. Sound reasonable? Manual Tranny: I want a smoother shift, and I've read that Mobile Synthetic is a good choice for this... I live where it snows, FYI. Specific recommendations. I believe the tranny shares with the front diff. Rear Diff: Not going to mess with for now... unless having different oils in the tranny and rear will cause problems. Thoughts?