Vitz, if you happen to buy a clean less driven one, will give u at most 14-15 km/l...
Passo, the new one, on the other hand is marvelous on fuel... A guy who was using good quality tires, oil, plugs and his car was Hana Plus swore to me that his car was easily giving him 16-17 km/l in City driving...
Personally, I would opt for a Passo, good value for money and resale is no more an issue...
Cheers...