I have been reading that Delvac1 (now sold as Mobil Truck and SUV Synthetic) may be ideal for my new Saab 9-5 high output Turbo (Aero). My only concern is that Delvac1 is not specifically rated as an approved oil by Saab (although it probably meets or even exceeds the standards of M1 0W40, which is approved). Would a 50-50 mix of Delvac and M1 make sense as a solution to get the benefits of both and still be able to maintain my record of using an "approved" oil? I live in So. Calif so cold weather is not a concern. I am new to this website and I have searched earlier posts, so hopefully I am not asking a question already answered. Thanks in advance for any input.