Mark I agree with you to some extent.
Also the proper "European" oil is 5W40.
The only problem I see arise with that is when I asked Mobil about which of their synthetic oils contained viscosity index improvers (not good for high rpms) and mainly gearing it towards their 0W30, 5W30, & 5W40 selection.
All they sent back was that their 5W30 did not use any?
Now they didn't say the 5W40 did, but they said the 0W30 did. Maybe whoever answered my question just didn't know about the 5W40 since they omitted the answer, but it put enough doubt in my mind to not switch to it for the summer.
Also I do routine oil analysis of my oil (Mobil 1 5W30) and the SUS viscosity (@210d), even after ~4k miles/4 months, is well above the average for a synthetic and miles above any conventional oil & the contaminents are well below either. This shows my filtering (K&N for both air & oil) & the oil's anti-wear characteristics are great.
So I am not too worried about it breaking down & if it can withstand my constant abuse it surely can take anyone elses...
