You know the car I drive.
when I bought it the previous owner went to shops and had them put API SM 5W30 in it along with cheap paper filter - its ok for 4000 miles, but the problem was found when I opened up the filter. The shop installing the filter did not know that the filter has to be assembled to a given mark on the filter cartridge - it takes a strong and careful push, If one does not pay attention the filtering does not happen and oil simply bypasses it because liquid will take the path of least resistance.
When I assembled the correct filter and used the Mobil1 0w40 oil it literally turned black as diesel oil in less than 500 miles. After 15000 miles of running this oil and filter the oil filter was very very dirty and the oil was literally black. The new oil put in has about 2000 miles on it now and it also has darkened, The quality of it is that the metal parts of the engine are a golden colour.
Hence I said, if I was a customer of this shop, I would get this statement written and signed and enjoy free oil changes for life.