I drive a VW tdi 5spd 40k miles a year commuting 95% highway. I manage about 48-49 mpg with it. Its me alone in the car so I dont really need my back seat if you get my drift. I drive 65-70 75% of the time and 70-75 the rest of the time. (pretty much flow of traffic around here) What Kind of fuel economy would I expect out of a manual insight given those variables?