Seems to be some confusion over 3.0 TDI road tax, the majority are less than 225k/gm so are £200 road tax. Mine is 3.0 TDI Quattro and is 223k/gm, check the registration document. This has been mentioned in another thread somewhere....
Main reason for better mpg in 2.7 is that a lot of them are 2wd, whereas all 3.0 are quattro..