Have a look here:
http://www.oople.com/forums/showthread.php?t=156211
With the amount of wear that I am now seeing on my diff out-drives I expect that I will be able to have them burried with me!
"welshmerlin" has been testing a coupling on his TM2 for me at the Silverstone track for a couple of months and has not seen any wear yet.
I have TM4 and TM2 couplings currently being assembled by a driver in Germany and hopefully these will be tested in the next week.
I also think, but cannot prove, that they make my car faster down the straight! Time will tell.
So far it appears that, so long as there is still some material holding the cup together, then I can recover the old ones. So long as the sliding puck/blade spans the notch it is as happy as Larry!
Bad news is that the four that I have in stock are currently promised to a guy in Belgium and I doubt that I will manage to make any more until the New Year.
Now that I have made a few, I shall be reviewing the price that I sell them for as they take a lot of time to make.