So I will be purchasing a 2004 BMW M3, beautiful condition only 40,000 original k. Now everyone screams to use castrol 10w-60, but their reasoning is because driving it hard increases the oil temp fast and hot. I def won't be tracking the car, maybe drive it a bit hard if you want to call it that at times. I would much rather use a thinner oil, something along the lines of a 5w-40 or 10w40 or maybe a 50 oil. Do you think a quality synthetic will provide the necessary protection as the castrol 10w-60 if not driven hard or tracked?