I have been through this process with eBay aftermarket keys. Of course, make sure you purchase the correct, complete transponder blank, and be ASBSOLUTELY CERTAIN that the locksmith has the equipment, know-how, and experience to cut this special, expensive sort of key. You will find not every locksmith is willing or able to perform this particular task, and it can sometimes be an experience with a fair degree of anxiety for both locksmith and customer.