We only use 93 Octane here in NJ for our XC60 T6 AWD R-Design, because it is a mere few pennies difference from 91 (Sunoco is the only ones that carries 91); salesman said to use 87 and we all laughed at him, and then I pointed out exactly in the owners manual which stated to get the MPGs/HP you need to use 91 and up! If it's a turbo engine I only use 93 octane; e.g. 1994 940 Turbo, 2004 S40 1.9t LSE, 2007 S60R, 2006 S60 2.5t. Though I tried putting 89 once in the S40 when gas prices started to get high and the car did not do very well with it; but then again the car already had like 45,000 miles of 93 only, lol! The dealer told me that it was perfectly fine to put regular (87) in the R and that I should; basically I felt like smacking him in the face, hehe! My Mazda is the only one that I put 87 regular in it, but then again its a 2.0L 4cly. NA motor, which will not benefit from higher octane fuel; I try to stick with good fuels like Sunoco, Shell and BP.
