My consumption did go down when Xcede was loaded on my car. IIRC, i use to average 10l/100km, im now sitting on 9l/100km, this is town driving.
I did one long distance trip and the different between pre-Xcede to post-Xcede was the same, so roughly about 1l/100km. But, this is with a heavy foot. With a lighter foot, im sure i can bring it down further.