Engine oil PENNZOIL or IDEMITSU

Subaru OEM oil is Idemitsu 0W-20. I currently use Idemitsu Zepro\* 0W-20, a high-moly formulation from the same manufacturer.

That's the wrong oil. You want the Idemitsu eco gold medalist advanced moly 0w-20, which is basically the same as Mazda oil(Idemitsu makes the mazda oil).

Pennzoil Ultra Platinum has been doing well in my UOAs.

Idemitsu zepro eco medalist advanced moly 0w-20. Basically the same thing as Mazda's oil.

I've switched to Pennzoil Platinum Pure Plus. It's cheap, it's easy to find, and it's got those nice lubricating additives that our hot-running FA20 motors and Garrett turbos like.

FA20s show regular positive results with Pennzoil Platinum PurePlus.

I run Pennzoil Platinum in mine (same engine) which is another popular oil. 5w-30 btw.

I use Castrol or Pennzoil most of the time (N/A engine or I'd use Rotella) haven't had any issues with it.

I have been driving for upwards of 50 years and have always had good luck with Pennzoil products. Pennzoil makes a 5W-40 full synthetic Platinum Euro which meets the VW 502 spec and has gotten good reviews from GTI owners.

I'm running Pennzoil Ultra Euro L 5w30. It's a low saps oil that's vw 504/507 approved. However, because of the high sulphur in US fuels, you can't run this oil longer than 5k miles. A low saps/low volatility oil will greatly reduce intake valve deposits proven by lubrizol.