Alright, let me get this out of the way real quick...
Originally Posted By: killagt
My local Subaru tell me to use only pennzoils 10w30 with subaru oil filer, and if im using something else it will avoid my warranty, so i just let them change my oils
Get this in writing from the dealer and then report them to SOA. They'll get chewed for that. The owner's manual gives specific instructions as to what oils (weight and certifications) you should use, and has no mention of brands. That being said, there are some oils that are better than others...and Pennzoil isn't neccessarily the best. Secondly, while studies have shown the Subaru oil filters to actually be top notch (if not the best) in quality, it is illegal for a manufacturer (who actually makes the call on warranty claims...not dealerships) to specify the use of their own oil filter or void your warranty.
Another thing, a manufacturer can not void a warranty, that can only deny a warranty claim. No matter what modification is done to the car, the manufacturer has to be able to prove that the modification done to the vehicle caused the failure (and again, it does not void the warranty on the entire car, just denies the related claim). The one exception is tampering with the odometer. If the odo is tampered with, the warranty can actually be voided.
No matter if you, the dealer, or a 3rd party shop does the oil change (properly), all are valid as long as you have reciepts.
Now back to the OP.
Do not run 5w30 Mobil 1. It has significant shearing problems even in the stock 2.0 WRX motor. I run 10w40 Redline year round in my STi (with a bit of 20w50 in the summer). I don't know how cold it gets where you are at, but if you can run a 5/10w40 year-round, do so. When you track the car, even consider a 50 weight if it isn't too cold outside.
DO:
-run at least 40 weight
-Use full synthetic
-change oil/filter after every 3k
-change oil (not nec. filter) before and shortly after each track day/HPDE
-check oil level bi-weekly (yes, at least twice a week)
Don't:
-run Mobil 1 5w30, ever.
-run less than a 40 weight unless you are in extreme cold and 5w40 is unavailable.
As far as what to run. I have had really good experience with the Redline. It is expensive and a bit of a hassle to acquire though. IIRC, Delo 400 Synthetic and Rotella Synthetic (both 5w40) have been getting good UOA results. I can find the Delo at a Costco 'Business Center' location and the Rotella at a random Wal-Mart in another part of town. I believe Pennzoil Platinum has also been getting good results in our cars.
