I've driven (2) LS Integras over the past 7 years. 1 coupe, 1 sedan. Both manuals. Both slightly modded (I,E,H). I've seen 22-24mpg (typically in the winter) due to gas additives and cold weather, and I've seen 30-33 in the summer while using the AC on longer highway trips. If I had to give an average over 7 years, I'd say 27-28mpg.