My imprezas been serviced on semi synth oil previously, so when doing an oil change naturally i grabbed semi off the shelf (magnatec)

I heard boxer engines prefer fully synth oil, is chaning to fully synth going to cause any problems at all?

 

Id stick with semi presonaly, and do an oil change every 3k or 3 months which ever ocours 1st.

I run my Type-R on 10-40 semi, and have no probs at all, best to use a genuine Subaru filter aswell

 

i run my 94wrx on mobile 1 15w-50 fully sin and av ad no problems at all.