I agree with @erik_squires, that you’re unlikely to find an off-the shelf replacement for your woofer that is functionally identical except for the voice coil former.
I think you’re also unlikely to find a recone kit for your woofer that has a titanium voice coil former.
Replacing the voice coil former itself is not for the faint-hearted. The voice coil will be glued to the voice coil former. And the final assembly needs to be round and sized within fairly tight tolerances.
Unless you have a very special set of skills, you might want to look for a speaker recone shop that can undertake what you have in mind. And you may find that it’s just not practical after all.
Getting back to Erik’s suggestions, building your own speakers (ideally starting with a kit) puts you on track for a lifetime of enjoyment of this hobby from a whole new participatory angle. Your interest in titanium voice coil formers implies that you are detail-oriented, and amateur speaker-building is very detail-oriented. It was my gateway drug to becoming a dealer and eventually a speaker manufacturer.
Duke