tonttu-
Not to challenge anyone or sounds like a *******, but IMHO been a race car driver of some sort doesn't necessarily implies that he knows more about motor oil than all other qualitifed engineers and mechanics.
I was a SCCA stock D class slalom race car driver in the past and back in those days I know less about motor oil than what I do now, especially after joining BITOG and learned more(much, much more) than I did in the past. Fortunately, I didn't ruin any of my cars simply because I stick with 10W30 all the way (switched to full synthetic as soon as they were available) and was able to get by a lot of cold, chilly winter mornings/nights with -36C and no engine block heater.
I still own one of these cars (my Mazda 323 with B6 block) and it's still running strong after so many years of faithful service under my rigid OCI regime. Did the AutoRx and now emission tests is like new again, except of having a rather lazy cat after so many years (still factory)
Just my thoughts on this oil subject. I know far more guys who claimed that they know everything and ruined their bearings/scuffed their cylinder bore simply because their oil pump was having an interesting time pumping thick motor oil during startups.... (grin)