Use an oil that meets the specifications set in your owner's manual and keep the oil change interval stated in the manual. Find something available locally for a price you are comfortable with, follow the manual, and go on with life.
Thanks. I was talking with a subie tech and he said they usually use an additive to help with turbo performance/life, so i just wanted a little feedback. He didnt say what he uses though and i just want to keep this motor running strong.
Ask exactly what (s)he uses and how it fits in with Subaru's stated policy on oil additives (their suggestions boil down to "forget it" and are in the owner's manual if memory serves).
I'm skeptical that there will be any data to support the additive use, but if there are and they show meaningful reduction in wear rates, even I would buy the stuff -- and the wear rates I've measured on my motor are very low anyway.
EDIT: A while back, I was discussing some oil analysis data via email with T. Dyson, who suggested his additive could reduce wear in my motor even more. I thought about this for a bit, and concluded that even if I were to accept the claim at face value -- and I have no reason not to, as his insights and contributions have certainly gained my respect -- I still don't see a need for the additive. If a motor is seeing single-digit wear rates, halving those rates is IMO meaningless; something else will fail before the motor does, making motor longevity as it relates to oil a moot point IMO.