I can't find anything that lists the current HTHS viscosity, the old SN version of FS 0W40 was 3.6 but the KV100 was only 12.9 the new version is 13.8, the HTHS of 3.9 for 5W40, I have only found on a French market PDS for an older SN product that may or may not be the same thing as the older FS/FSX2 SN formulation we had here that had a KV100 of 13.7, while the KV100 of the new US market version of FS 5W-40 is 13.2. Mobil 0W-40 is probably the most recommended because for years it was Mobil's only US market A3/B4 oil with a wide range of Euro approvals, the FS(X2) 5W-40 product has only been around for around 2 years and they very recently added FS 5w30 to the US market, so I guess old habits just never die.