so i called volvo of north america today and realized that they arent of much use unless i want to get a stereo code or a accesories catalog sent to me. the women was about as knowledable about volvos as i am about the physical of cold fusion. does anyone run diffrent oil in their R than 5-30 and 0-40? i know mobil 0-40 is recommneded for performance engines such as mercedes AMG, Porsche and other high end vehicles. i used 0-40 in my past 3 cars and it made all of them run great and 2 of the 3 were 130K and 230K on the cars with stock turbos. so my question is does anyone use 0-40? how has it worked? has the dealer had anything to say about it?