I used it in my 2009 Subaru Forester. Main reason was the unique situation with the Subaru manual transmission: Hypoid front differential located internally in the manual transmission sharing gear oil with it. Yellow metals in the transmission's synchro's do better with a GL4 but hypoid diff needs GL5. Could not use any gear oil with friction modifiers in it due to the synchro's. The formulation of the Eneos 75W-90 at the time was a decent compromise for the situation. I have only anecdotal info about it's performance however since I traded the car in before doing the next scheduled gear oil change on trans and rear diff (had it in rear diff too). I do know that it's not synthetic, or at least it wasn't at the time. I had emailed a company tech rep and their reply said it was not synthetic and that the performance criteria were accomplished with a conventional base oil. But that was in about 2011, so formulation could have changed since.