The car will already have it has standard.
You would be better to buy a used remote fob on ebay, then the car security codes, then an Elm and a licence for
MES - then you can pair up a remote fob.
From what I was lead to believe.
All cars have the factory module and antenna in the roof lining...
The option to pay extra for it covers the cost of a remote key.
My car was never supplied with a remote fob but it did have the module etc, i have done the above and have a working remote fob - still need to get the blade cut and pair the chip to my ecu so it will start the car but for now a remote fob is far more handy than having to use the key every time.
Hope this helps.