I have also just tried a bottle of the Liqui Moly SPEED TEC Diesel whilst I wait for the Wurth products.
I must say it is pretty good! Sells for $20 - $25 at various Supercheap / autObarn retailers.
LIQUI-MOLY Fuel and Oil Treatments & Additives

Out of interest, has anyone tried the Liqui Moly TOP TEC 4200 5W-30 engine oil?
It has the following approval VW 504.00/507.00.

I am interested in trying it...