I decided to attack the headrest repair on my 02 XKR the other day. I printed off the TSB so I had the instructions in front of me. The passenger side had not been done, so I decided to skip the shrink tube method as it did not seem to be the best fix. Instead, I cut the cable housing at the lower crimp fitting. I then cleaned the fitting and reinstalled on the cable housing. After testing repair and putting seat back together, I started on the driver side. There I had found that it had been repaired according to the TSB. Not surprised that I found the heat shrink tubing had stretched at the housing cut, thus shortening the cable again. Thought for a few moments on how to reattach the separated cable housing. I found a roll of two inch wide metal/aluminum tape that is used to connect metal duct work in houses. I wrapped a couple 2-3 inch long pieces around the cable housing and then wrapped the metal tape and beyond an inch or two with black electrical tape. I feel confident that the metal tape will hold longer and not stretch like the shrink tubing did. I wanted to post a picture of the tubing but have not figured out how to attach photo's yet. I hope this might help someone who finds that the prior repair did not hold up over time.

 

Hi Everyone,I would like to contribute to this well-known issue of XK8/XKR and the solution to fix it.
Forget about the heat shrink tubing method. Given the tension, I bet it will eventually come loose.

Instead, I found a Nyon Fuel Line Press Fit Union 5/16" from my local auto parts store. It works like a charm.
It has metal teeth inside to grab on the cable and it has plastic housing. Works perfectly.
I have one extra piece of the press fit union available if anyone is interested.
Total cable
removal is 20mm, that is 12mm + 8mm to account for the extra spacing from the Press Fit union.