Hi,
Just thought I should share my recent experience with the i30 CRDI economy. On a full tank I managed 1300km on a recent trip from Canberra to Sydney, then back to Goulburn, then back to Sydney, and then the remainder in the Sydney areas of M5 and M7. It was about 50-50 highway and Sydney driving.
I would get at least 1050km around town on a full tank (I have a heavy foot), but it's the first time I managed 1300km (on a light foot). I am still amazed by this, as were all my friends when I told them. I probably could have squeezed a little more if I was a bit more dicaplined. I attribute this to the tuning box which I bought from Germany several months ago. The fuel that I used on this occasion was standard fuel from an an independent service station (United) and the vehicle has just traveled 70,000km. But I usually use the Woolworths stuff 99.9% of the time.
Nevertheless I'm stoked with its economy and performance from my tuning boxed i30.