Aik dua hoti hai Allah Naseeb Karay. It means that Allah blesses us to enjoy what he has given us. Having and thing is just one side of the coin and enjoying it is another. I pray Allah bless us all with the both. Life is short and the world is not a permanent place. All these models are going to put on more years as you cannot stop the time.
Remember owning a diesel car esp 2.0D was considered the ultimate thing in economy drive. It was a hot cake, but the change in POL prices turned the tables. Now those cars with diesel engines have low resale. That is how things change, today's market cars could be tomorrow's lemons.
It is September and I think that in two month's time car sales would plummet to zero level. Nobody would be buying to get just 2012 on the reg book for the same car. If the model is changing then one can wait, but if just the figure has to change then it is waste of time and money. You can take advantage of ready delivery, no own and even discounts in Nov-Dec-Early Jan. You are not going to suffer that much loss for the reg book entry.