What exactly are you trying to fix? Is the keyhead simply worn? You can buy a replacement keyhead button portion for about $15, and you reuse the key shaft, immobilizer pill, and electronics.
If something else is broken, then you would have to address that. There are 3 parts to the key in general: the key shaft itself, the immobilizer 'pill', and the remote control (door locks and alarm).
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Demick
'04 Boxster S
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