In my personal opinion, ASE papers don't mean squat. In over a decade of being the face of my business - the guy you see at the counter and the guy that answers the phone - I have been asked a grand total of THREE times if I have ASE certifications, etc. In each case I explained what that really means and the customer brought me their car anyway. It's a waste of time and effort - much like college. I can get the same or better education for $12 in late fees at the public library and as regards "auto mechanics" - which isn't really a term I like - I prefer "machinist" - as in someone that is involved in building, understanding, and repairing machines in general - I don't really limit myself to automotive......
Oil viscosity and additive package is chosen by the manufacturer based on emissions, fuel economy, emissions, bearing loads, emissions, longevity, emissions, maintenance cost and interval, emissions...... oh and did I mention emissions?
If you want the best protection then you really only need to consider the load on the engine. Higher viscosity resists being squeezed out of the bearings. That's why the higher power engines (turbo and H6) specified 5w30 rather than the 5w20 used in the newer NA engines. The construction of the engine internally - oil pump sizing, bearing clearances, etc - is no different between engines that "recommend" different viscosities. In general the manufacturer chooses the thinnest oil they can "get away with" that has the lowest additive package they can "get away with" and thus have the lowest emissions and least damage to emissions equipment (which has a federally mandated extended warranty). If you look at many of the high powered factory cars.... BMW for example ran 10w60 on many of their high powered turbo engines from the factory.
We use exclusively 5w40 and higher viscosity in all our oil changes unless there is specific concern about voiding a warranty, etc. Anything above about 400 HP we use 5w50. I have been using this policy on EVERY car we service - probably about 1000 oil changes a year - for about 8 years at this point. We are an Amsoil dealer and our go-to oil is the 5w40 Euro Full SAPS formula (black lid). The high power cars get the 5w50 Signature Series. We use WIX filters. We set all the oil change intervals for 6,000 miles and we always remind people to check their oil level regularly.
I have lots of customers making 500+ WHP on Amsoil and I have torn down a LOT of engines - I have never seen a single failure of one of our engine builds that could be logically linked to a failure of the oil to prevent metal-to-metal contact.
And for that matter - 99.999% of every engine failure I have seen has been related to the engine running low on oil, or being starved of oil. The type of oil matters very little when it's littered with debris from bearings that are starved of oil every time you take a hard corner (low oil level) and from people starting and driving with the engine cold and the bearing clearances half what they are at operating temp and the oil filter in bypass just shoving all that oil and debris through the bearings like a lapping compound.
You want the engine to last? Run a high quality synthetic and a filter with an up-front bypass design. Don't drive it hard when it's cold - you'll just put the filter in bypass and main bearing clearances are tight when cold. Keep it topped off. Change it on a regular schedule.
The Brand of the oil is pretty much irrelevant. Amsoil, Redline, Royal Purple, Lubri-Moly, Motul, etc..... it's pretty much all just marketing. They will all do the same job if you keep it full and clean. Do this and the engine will live plenty long enough to leak from everywhere and lose the HG's and end up being junk since it's cheaper to just get a JDM replacement. Timing components aren't a concern and none of them can read the label on the bottle of oil you pour in.
GD