Terry, tel the MIL to read the maual carefully. In my 98 manual it clearly says 87 is the minimum. I have a N/A (non-turbo) S70 and have been feeding it 87 (regular in these parts) since new. No issues at all (almost 23K miles on the clock new). I, like youself, tried super and the biggest difference I felt was in my wallet. I do run fuel injector cleaner now and again to make up for fewer detergents in regular gas. Oh, I also drive the car rather hard (it loves being above 4K RPM).