Originally Posted by mimmitt
No one has had it long enough to accurately answer this. However I can tell you that I don't expect it to improve my horrific MPG; I drive the car in DS all of the time in quite a bit of stop and go traffic. WTF though, I bought it to enjoy it.
On the freeway the 135i seems to do pretty good... Long trips cruise control at 75-80 will get you like 28mpg, but step on it once or twice to merge and voila you're back down to 25-26mpg even on the freeway with no traffic. LOL
Spirited city driving gets me around 19 (normal about 21), but if I do a sporty 40mile hillclimb run and come back, I practically have to refuel right when I come back down the mountain, averaging a solid 9mpg x-D
$1000-1500 bucks for a 20hp/37tq that retains factory warranty is pretty good so I am considering this. Hopefully my dealership knows what I am asking them for when I say I want the ZMZ code retrofitted to my 135i.