Hi, I dont have any experience of either model that you are interested in but I can definitely say from experience that you should not order unless you have driven the exact model that you are interested in.
Did your dealer not offer to get you one in from another branch in the specification you are thinking about? This can usually be done even if it takes a few days but if he didnt offer that I would look for another Nissan dealer in your area and ring and see if they have one you can try. Unfortunately most demonstrators are often top specifiction models so it may have to be a used model but this doesnt matter if its the same up todate model and same specification.
As for the heated seats I have similair issues as to yourself and would not buy any model without them, get it wrong and you will regret it for the length of your lease. Exact model and spec. is a must,
Good luck.