I exchanged a couple of emails with Eneos in the U.S. a while ago as I was very much interested in trying their 0W20 grade one. They said Sustina base oil does not belong to any of VHVI, PAO, Ester as it is based on Eneos Proprietary W Base oil. They also said any of Sustina oils are good for high speed/high temparature driving as its base oil is very stable though. I don't know what W-Base oil is, but may be a mixture of all three?