8100 0W-40 thins like many other oils and can be even less shear stable then M1 0W-40, at least with temporary viscosity loss. HT/HS 3.66 is quite normal for all actual compositions, even for 5W-40 synthetics, irrespective of oil manufacturer (6100 5W-40 Synergie or 8100 5W-40 now has 3.57). Everything is made to reduce mileage, but unfortunately it is often at the expense of lower wear protection.
Like with 300V its corrosion activity is 25-40 % higher then with PAO or PAO + HC synthetics. Base stock is not 100 % esters: there was an amount of PAO that may be substituted now by HC where the increase in NOACK.
As I could understand it was more important for Motul to get first VW 503.01 approval rather then MB 229.5 (probably some marketing reasons). In wear tests 229.3 is more rigid then 229.5, so next figure or letter does not mean better.
Subjectively with 8100 0W-40 works quieter then with M1 0W-40 or Castrol Formula SLX 0W-30, but I don't have possibility to make oil analysis. It's a good oil, but nothing exceptional, if we may still find something exceptional nowadays.
As for Motul esters, given oil properties of their all esters based oils it does not look Motul uses the best ones.
Unfortunately my PC does not like to work at this Forum (apparently bacause of PC age), so before I get ordered notebook I shall not be able to actively participate in your discussion. Sorry.
Asmodeus, est-ce qu'a Quebec on apprend maintenant le francais sur les livres du type "Zizie dans le metro" ?