It's the only synthetic oil he will use. Let's just say I trust the guy implicitly, he holds a competition racing licence, owns a Bosch Service Center and is actively involved with some of the top Audi tuners in the USA. A pile of blown European engines is the backdrop for our ongoing conversation, most of those hunks were running Mobil 1. He claims building oil pressure is a problem with Mobil 1 (15w-50, I assume) and he sees many lower engine failures on the M1. I relayed the argument that M1 is the most popular oil and motorheads who will beat-on and destroy their cars just *happened* to be running M1. He says no. He has experienced the same "incidents" that destroyed Porsche and S-car engines on Mobil 1...with the 50 weight Syntec "never" a failure. Again, I trust the guy, 25 years a Master Porsche+Audi mechanic, his dad 40 years a master BMW mechanic. He even said he will not bother discussing motor oils with any other customer except me, but explained the extreme pressures the 50 weight oil handles makes it the only choice for him (and his customers since he had 2 full drums of it) also he "hates" Mobil 1. BTW- regular oil for his customers is Castrol GTX 15w-40, possibly a HDEO version. Are we missing out on a good synthetic oil with the Syntec 5w-50? Is the VII shear really an issue? ps I know that SAE 40 or 50 is too thick for some engines, not Euro cars though. Maybe good for hi-mi cars when hi-mi oil is too low-performance.