My thought is that ACEA A3/B4 and C3 tests have such a stringent high bar than any oil that can pass the ACEA tests could easily pass the API SP tests with flying colors. My thinking is: If a car doesn't burn any oil, then the high phosphorous / high zinc levels in ACEA A3/B4 can be a good choice. If a car consumes some oil, then the ACEA C3 with its lower phosphorous/zinc is a good choice to protect the catalytic converter.I mentioned SN+ and SP because they both have a LSPI test and SP contains the TGDI chain wear test. The euro certs I mentioned have a chain wear test performed on their own GTDI engines. I only know the tests exists but I'm not aware of how they compare to API. Seeing as the tests under SN+/SP are performed on a highly modified* TGDI engine it may be more stringent if not equally stringent.
*ex, modified rings which introduce excess soot into the crank case.
But due to the lower cost, I am generally using the lowest cost full synthetic 5W-30 oils I can find with the Dexos 1 Gen 3 certification which is more stringent than API SP. My thinking is that any full synthetic is good enough for 10k OCI, but I prefer shorter OCI for my particular application.