Dear friends, what oil does our “infarct-endangered” 9-3er/9-5er engines get best? As I read here, it should be a synthetic best quality. These include according to my “sortiment research” Shell helix ultra and Mobil 1, respectively than 0W-40. However, the Shell product is considerably more expensive than the Mobil 1. Is it also so much better and do the Saab machines actually need it for a realistic (over)life chance? Or doesn’t it also do Mobile 1? What do the experts mean? I’m curious. Viggo Saabquist