Did you measure the optimism? I only ask because the TiD's trip computer was on average 4% optimistic, so sometimes it was almost spot on, sometimes it was pessimistic and sometimes optimistic by about 8%. Some of this I put down to the auxiliary fuel heater. Most of it is down to how the ECU guestimates economy.
The tuning box made no difference to accuracy, though...
The petrol 1.8t's trip computer is almost always 7% optimistic. So it showing a shocking 36.2 really means it's only averaged 33.6 there or there abouts. :-(
Exactly and certainly not caning it.
This is the reason why the original TDI engines are - arguably - the best. I remember selling the mark three TDI by the bucket load to farmers for their kids - 90 bhp, >50 mpg, spacious, VW badge. In the Passats we had, we favoured the 110 version - better paper economy, same in the real world, but felt a *lot* quicker.
Did you strap the MG ZR's bonnet to the Golf's bonnet to improve the aerodynamics... ;)
That and 58 to the gallon are bloody good going, basically.
The highest brim to brim figure my 9-3 showed me was 56.0, showing 59.1 on the trip computer, over 630 odd miles.