I don't believe there is a difference in brands. It all has to meet the same standards to be TC-W3.
Why is this not true for SN rated oils.... lol.
Do you mean there is no standard or specification required to be labeled a SN oil?
What I meant is that many people indicate some SN oils to be "better" than other SN oils, when SN indicates a specific performance spec.
People rave about PYB, it is SN as is my $1.50/qt Citgo oil. Good chance it is better, but can there not be "better TC-W3" than others?
I'm at the point where SN, TC-W3 etc is "good enough"