I was (until my undertray/engine shield broke) getting about 43.5MPG on the highway doing 100KPH (60 mph) . This is with a 5spd manual. The manual really needs a 6th gear or a longer/taller overdrive gear.
The MPG with a taller overdrive gear would be much higher as it would allow for a higher speed@lower rpm.
Make absolutely no sense when EPA and CAFE requirements are screaming for higher fuel economy.