Hello Norbert - Grüss Gott!
Apologies for my slow reply but I blame it on the chaos caused by family visits at Christmas
The torsion propshaft does away with the rubber 'doughnut'; it is a more modern solution and can handle huge amounts of power if needed. The engineer who fitted my 131 gearbox suggested it and sourced it from from Bailey Morris Ltd as shown on the label in one of the pictures. He gave them the required dimensions and they produced it. I can't remember how much I paid but I think it was around £2-300. I'm very pleased with the result.
I'm not sure what you meant by 'what did I do with the shifter' but the 131 gearbox needs to have the remote shifter - sometimes known (incorrectly!) as the 'Abarth shifter' - otherwise the stick will hit the dashboard. Because the stick sits around 8-10 cm further back with the remote shifter I had to cut out the ashtray from the centre console and make a new wooden cover to surround the shifter.
The engine was lowered by around 20-25 mm by using race engine mounts. This gave enough clearance to fit the 131 gearbox without needing to cut any of the transmission tunnel away. You'll see from the pictures that the crossmember had to have a small edge cut out to clear the sump as the engine had moved down and slightly rearwards.
The only pictures I have are on this thread a few pages back.
I hope this is useful and please let me know if you need any more help.
Regards,
Phil