Does the Murano need to have something special to use the smart key? Or can you just buy one and have it programmed for any Murano?

Not totally sure. You should call a local Nissan dealer to ask. My guess would be that the car would have to have the sensor in order to use a smart key. As long as it has the sensor you should be able to reprogram any smart key to your car.

If it had one to start with, you can replace it and have it programmed by a dealer, if it did not come with one I think you are out of luck. They are pretty expensive to replace, I have seen keys that are 300 to 400 dollars.

Mine has a smart key, but mine is an SL, It would probably end up costing you a over $1000 if it could be installed considering the keys are $350 each... like someone else said, I'd call a local nissan dealer and discuss it with them.

I highly doubt that you can get a smart key for it, as any Murano I've worked on knows if the key is inside or outside of the vehicle, and I mean the difference between 3 inches inside the window and 3 inches outside the window.