The oil doesnt really thicken with heat, 10w60/40/30 means that the oil will be a 10w when cold, and it wont thin out more than a 60/50/40w oil would be when it is hot.

so it is like putting a cold straight saw10 into your engine when it is cold, and once it warms up putting a hot (100 deg) SAE50 into your engine

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Version 6 STI