At a recent service of my Auris, I changed from Motul Eco-clean C2 0W30, to Toyota Genuine Formula XS 0W20. The difference was actually shocking. Free revving, less need to downshift and the consumption improved at least 5mpg. This was a great surprise given that the Motul is an extremely thin 0W30. This engine (1NR-FE) clearly needs thin oil and perhaps a dose of moly? It even seems to prefer the Formula XS over the Eneos 0W20 I had in previously. I think the Formula XS in europe/UK is XOM. Unfortunately, it cost $16-18/L. I try and pick it up cheap on eBay if possible. My other option in Honda Genuine 0W20 which i believe is Total made and substantially cheaper.