Hello again John, i may have miss heard gavin but i thought he said that the system would be invisible to mechanics as long as i had re-programmed the car back to the standard map. if i leave the modified map in the ecu then the mechanics lap top will read all the modified settings, the dual sytem works (i think) by removing the original map and storing on a chip then uploading a modified map to the ecu, when you want the standard map back on the car you do the reverse.
I have now had the mod on my car for three weeks and have just refilled the tank with diesel, i used to get around 50 + mpg driving steady but now get 55 + mpg which isnt far short of the 12% better economy quoted by gavin, since refilling my alhambra has done 106 miles and the needle is showing 16th of a tank used which equates to about 650 miles to the tank, i am very happy with it. one word of warning though my car does appear to have higher smoke emmissions when towing, this i am assured is normal due to the high amount of torque being used at fairly low revs.