from my experience, if you're running boost all the time, go for higher weight oils like castrol edge 10W-60..

but for normal usage where running boost only when overtaking, go for normal reputable oils. i'm using chemlube semi synthetic 10W-40 with estherbond.

but the important thing is actually how often you change your engine oil. the part that die first is actually the turbo due to impurities in the engine oil. i change mine every 5000-6000km.