Originally Posted by Xinterp
^ Isn't there supposedly a gain in Fuel Efficiency? Or is that the 1 Series M coupe?
Supposedly. Someone with a 2011 135i convertible who recently did a Performance Center Delivery reported 30+ MPG average on the highway. I managed this on the highway:
(CONSP = Consumption, 36.1mpg average)
A more realistic average for every day driving is in the mid 20s.
The N54s aren't too bad either though, I believe.