why not ask the casa? i am sure you won't be charged for just asking.. and if they can indeed supply you with just the right key, then i gather you will have made a substantial saving.
no it doesnt work that way, the casa will give you a key and will just reprogram the transponder of the new key to correspond to your car(i think it's 5k if it's a bmw or mb it would cost you 50-70k(laser cut keys plus transponder))
you can even copy the immobilizer with the key duplicate, it is actually being done in the third floor of market market(bgc) key duplicate section that is if you have the original key(1,500 php)
oo nga pala to add if ever you want to copy your key with the immobilizer, never leave the key of your car to the duplicator and make sure he doesn't know the plate no. of your vehicle and he doesn't have a copy of your key.
may nagreklamo na diyan pero buti na lang fast thinker yung owner na nagpacopy ng transponder/immobilizer