Friends; for all of us 5-spd Insight owners, few truly realize how much benefit highway cruizing in lean burn is providing! Do NOT underestimate it. I roughly calculate the lean burn catalyst system is good for 18.65 extra mpg, or about 23%, compared to the same car without a lean burn system. This is huge! In fact, achieving mpg in the 80's and 90's is directly related to one's ability to slow down slighty & remain in lean burn mode as much as possible. Billy.....