Vezel only came in 2014 so there's no 2013 model. As for the specs and difference between X and Z, I would suggest you go through the below thread by late Dr. Zac (Allah on kee maghfirat farmaye, aameen), you can have a pretty good idea of what a Vezel is. Even the first post will answer a lot of your questions.
My Z package has black interior so Z package comes in colored and black interior both. It gives me 15.5km/l with A/c and 16.5km/l without A/c. A full tank of Hi Octane, which is normally about 35-36 liters gives me approx 600km and my drive for the whole month is around 1000-1200km, so only 2 fuel tanks per month i.e. Rs.7,000 approx.
X package has cruise control, multi steering, push start etc. just like the Z. The major differences are in the design of alloy wheels, absence of roof rails, absence of dual a/c which means both driver and passenger will get same amount of air and temperature. To be honest, most of these features can easily be compromised when you compare a 200,000 or more reduction in price.
I had driven a few Prius as I like the 1.8l version for its shape, and I knew fully well that it will come second best to Vezel in terms of pick up, but I was put off by the low road clearance, given the condition of our roads.
