Vekke, you seem to have done quite a few mods after putting in the WS2, but have you seen any further improvement ?
After the fill-up on 2012-06-15, I've had the car serviced (new filters all around) and put 1g/L into the oil, so around 1200 ppm by weight.
I've done 600km since the oil change.
There's no noticeable difference in fuel consumption at any speed.
The engine doesn't appear to run smoother or quieter than before with fresh oil.
The good part is that the oil filter to the turbo hasn't gotten clogged with WS2 either