Motul 8100 Xcess 5W-40 or Castrol EDGE 5W-40 are what I'll be looking into when I buy my RS. I've used both of these brands on the Subaru over the last 9 years with no issues all be it a different grade of oil but I'll be sticking with them brands for the RS.

Although Motul recommend the Motul 5W-40 OEM. Heres a link: http://ltbautosports.com/mooemspoi.html