Some interesting replies here - i guess most of you all run the 3.5 where as here in Australia we run the 3.2, and going on 300mi = 482.80km i get an average with hwy driving of 520km in winter and 500km in summer - AC doesn't make that much difference really. I use Caltex Vortex Premium 98 and do notice a difference if i run 95 or 91. 20 inch rims help to i believe.