Wondering which one would be best. Been using AMSOIL 5w30 or 0w30 as well as Redline 5w30 but wanted to switch to Schaeffer. I have a 2004 Volvo S60 R, 2.5L turbo with 90,000 miles. Volvo manual recommends 5w30 but Volvo Europe their Volvo VDS, VDS-2 and VDS-3 recommend either the Schaeffer 7000 15W40 or 9000 5w40. Any thoughts?