I have heard that the used car values are starting to drop, so if you are going to take advantage and can get a new one cheap, it may be the best time to do it.
But, being the cheap bastard that I am, I would run the numbers and see how much it would cost me.
If you are not making payments now, then will you be able to trade and get the new one without payments? If you are making payments now, you will be on the new one, but for a renewed loan term, which would be a big fat NO for me.
Run the numbers and decide if the new whiz-bang features are worth it. 23k miles on a car is nothing and the car is 4 years old? Doesn't seem like it would be worth it with the number of miles you drive (under 6k per year).