Used to do 45/41 like the sticker says. I never understand why the car understeer so badly in canyon driving. A friend said factory went 45/41 for the mpg (who knows?), and recommended 36/37. I have been doing 36/37 since. The car still understeers, although not as bad as before. However I think there's little difference if you just do freeway and regular street driving, maybe a bit stiffer over bumps with 45/41.