I drive m54 3.0i.

Wife's car with 450 ft·lb and 8 speed transmission is how it pulls off the relatively amazing mpg. That said, we looked into the 35i and 30i as a way to keep similar performance to what we are accustomed but get better mpg.

I don't believe for a minute the n52 won't best the n63 in mpg because my m54 from 2001 does about exactly the same as wife's.

Oh: lead foot costs a LOT. Studies show that $3.00 gas is suddenly $4.00 gas if you are a fan of jack rabbit starts. However that should not apply here as OP said that the mpg issue is on highway commutes.

One last thought. Reset your consumption meter with cruise on at 65-70 and see where it stabilizes. It should be at least 20-21. If not there is a problem that can be addressed.

Second last thought: winter gas screws with mpg. Did the mpg recently drop?

__________________
2011 E70 • N55 (me)
2012 E70 • N63 (wife)