supply and demand...
do your homework and see what kind of supply is anywhere near you... if there is nothing, all you can do is put in offers of what you are comfortable with and go from there. they can say no, you can say no and so on....
this time of year is tricky. 2016's are pretty much done. not sure what the current incentives are on the 3, but i'm sure it's better than what would be on the 2017 model. the question becomes are they good enough to warrant buying the car that will be "last years model" at that discounted price, plus have to add on the features they are speaking of.
me, i'd say i'm not happy with that and will order a 2017 without the added "features" they are installing. likely the increase in msrp from year to year will be minimal, so the actual price will be less for the year newer, but rates, etc. might be worse. when they see you are a real buyer and not willing to put up with goofy costs, they can either take a deposit and put you in the books for a 2017, or look into how much they want to move the '16 and give you a price more suitable.