Hi @oilman
Hoping for some advice on the below spec. Looking through threads I'm expecting you to say 5w40. If so, out of interest, why not the 5w30 the dealers/manual, states? Thanks!
Model: WRX STIYear: 2014Engine: 22k miles. I believe the last Subaru service states 5w30 petronas oil was used.Performance modifications: None, maybe an air oil seperator at some point.Driving style: Road, daily driving, no track.Power: Factory 300bhp