I've decided to use Motul 300v which as you're all well aware is a true synthetic ester base oil. I took my car for a setting-up session on the rolling road last friday, and whilst there I asked the top mechanic what his thoughts were on oil. The place I took it to is a specialist and has been in business tuning these cars for 10 years...What he doesn't know about them really isn't worth knowing! Anyway, he said to avoid fully synthetic because simply it is too thin and will simply seep past the turbo seals. Ok I thought, maybe he knows plenty about the car but as a grease monkey he's certainly know chemist! Anyway, the conversation went on and he said that none of the hybrid turbo manufacturers in the Uk will guarantee there turbo's with the use of fully synth oil. It sounded crazy to me simply becuase it goes against everything I have ever read regarding synths and there shear stability etc. Yesterday I decided to call a few of the main Hybrid Turbo manufacturers and as the tuner said not one of them recommends the use of true synthetics! There only reasoing behind this was that synthetics were, and I quote "TOO THIN AND WILL CAUSE AN EXCESS OF OIL TO SEEP PAST THE TURBO SEALS KNACKERING YOUR TURBO"! How can all of these so called experts be so un-educated on such an important subject! It's sort of got me questioning my own sanity...Is there any truth or are am I dealing with serious BS????