Well FWIW, I've always fed my GTI on SUL, but had to resort to NUL lat week for a tank
![ashamed :ashamed:](https://www.mk5golfgti.co.uk/forum/Smileys/newsmileys/ashamed.gif)
It didn't seem to make THAT much difference to the performance (but in all fairness, I was only driving to and from Borth - 150mille round trip, with the family, so I couldn't boot it)
However, my MPG got HAMMERED!!!!
![surprised :surprised:](https://www.mk5golfgti.co.uk/forum/Smileys/newsmileys/surprised.gif)
The best I could get out of it was circa 27/28mpg. The same circumstances with SUL, would be another 10mpg (or thereabouts)
I won't be going back to NUL unless really pushed.
Dan
![happy2 :happy2:](https://www.mk5golfgti.co.uk/forum/Smileys/newsmileys/happy2.gif)