I have an auto R33 GTST with turbo back zorst. I get 450-500 KMs to a full tank. So it comes down as low as 13 litres per 100 KM/h. Not bad for a turbo car.
If you want something different, order the new GTR. I can tell you now that 99% of SAU users won't be able to afford one...
The majority of the new GTR owners will be middle aged men with some decent cash on the side.