With me it helped. I was getting 17 before M. After I get 19-20. But there are people with M that would be happy with 17.

 

I wouldn't go so far as to say that the M flash corrects all the gas mileage issues. The vast majority of owners noticed an improvement in mileage after the flash, in the range of 7 to 15%. Some saw no improvement, others actually saw a decrease. There are over 50 threads to be read on this site concerning gas mileage, and most boil down to this- your mileage depends on your driving style (from granny shifting to driving it like you stole it) and what type of driving you normally do (city vs. highway, stop and go, etc...). Most owners average 16 to 24 mpg- though a few can't seem to get over 12! One thread specifically looked at whether early builds were more prone to poor mileage, and determined that was not the case. Though mileage in an RX8 is somewhat variable, I would think you have at least a 95% chance of getting a car with average mileage- and for me, 95 out of 100 is pretty good odds!