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I have been using Royal Purple XPR 10-40. XPR is not their regular Synthetic, it's their race version which has more film strength that helps with cold start. It leaves a thin film layer of oil. The engine runs smoother and it burns less oil. When I used Mobil, I used to burn 1 quart every 1k miles but with RP XPR, I'm only burning a quart every 5k miles. The oil temp was the same with Mobil vs Royal purple. I was hoping it would be cooler since it has a very good film strength. On the track, a friend of mine noticed that RP XPR was about 30F degrees cooler but in regular driving, I don't think there is any difference. He used to run 270F on track with Mobil but he was running 230-240F with XPR.

I want to use XPR 10-60 on my next oil change. What do you guys think about using a XPR 10-60 in a M157 engine(2011-2013 S63)? Would it have any issues with valve clearance? Would it run cooler?

Keep it simple and just use 5w40 for european cars, Motul, RedLine, LiquiMoly

or any 229.5 spec oil will do really.