Metro and Co. 6/23 was my last pre swap tank @39.8?mpg and 6/25 was the first post swap tank @43.?mpg. I have not gone consistently slow enough to see real results. Having the no torque b1 engine and the dpfi don't help.
Unfortunately I don't have solid data. Before the swap my driving habits were fairly aggressive, and I averaged near the EPA combined average at 24-25mpg. After the swap I took a job 2 miles from home and stopped topping off the tank, so I didn't keep records. 2 years later I got a job 35 miles away with a long freeway commute. My driving habits also calmed down so my mpg jumped up.