Did this some months ago: the repair cable is really expensive, was about 450€ here in germany. The whole cable is >100€ cheaper than the repair cable - no one knows why
I just repaired using a used cable (from an 4.4i pre facelift - part number didn't match but was the same diameter, length, aso) and tore apart the left side interieur (driver seat, backseat, B column trim, ...) took about 3-4 hours but I wasn't in a hurry and vaccuumed and stuff.

I've seen a video later where someone repaired it: https://www.youtube.com/watch?v=s-XO98LOa3Q
Don't know if this will help...