I got my car few weeks back and I paid 7500 which they asked me as Registration charges.
The user manual clearly says the key has an inbuilt immobilizer.
In order to verify it I went to a pavement key cutter and Mr. M*nt to get a duplicate key. Both of them verified that their keys won't work on my car as the key contains a metal tag with the unique number which is there to identify the immobilizer signal.
So i don't see any point in you paying more for a factory made feature.