Sorry if this thread is obligatorily redundant. I've searched and read the oil thread in the FAQ, but still quite curious about several points and would like to share some interesting findings.
I am using Total Quartz 9000 5W30 oil in my 2007 Legacy 2.0GT since the recent service, following the owner's manual service data:
In other posts I found that people would prefer W40, W50 or higher oil to prevent oil burning or to protect the engine (don't know if all for tracks). In my understanding it's better to use higher viscosity oil for harsh driving conditions like track use and stop-start short trip, just like when using the car as a daily grocery-getter. So here's my question: is it advisable to use higher viscosity oil even if no track use intended, or just better off keep to the service data?
I am using Total oil only because my friend's workshop is Total authorised so I can have discount. It came to my notice that Subaru genuine oil may be a rebadged Total (some hearsay told me some may be rebadged Idemitsu though).
Subaru obviously doesn't produce engine oil itself, nor does it explicitly disclose the manufacturer or data of the "SUBARU Genuine Motor Oil" stated in the service data. On the Japanese official website we could notice at lease one SLX 5W40 is produced by Castrol (https://www.subaru.jp/accessory/engine_oil/)
Its top of the line oil on the other hand are indeed produced by Elf (or Total depending on how you see it): SUBARU LES PLÉIADES ZÉRO 0W-30 and SUBARU LES PLÉIADES 10W-50 (an option listed in service data) (http://www.pleiades-zero.com/). So I guess by some stretch using a Total quality oil may not be a bad idea, since Total may know how their products work in a Subaru.
What is your choice on oil brand and viscosity for non-track use?