Did not use anything from the M5 board. Worked together with FUGO from the German 7-board, he has a E32 750 BiTurbo, he lives in the Czech Republic. He made the repair already 2-3 years ago, and he sent me the seals he used.
We tested them on the Alpina and now I ordered more.
The standard LAD shocks: I sent him the samples of a shock we disassembled in Japan, but he checked it and said he needs the complete shock to see and measure also the steel parts where the seals go in. So he got another complete shock and measured that and now I get the first 20 sets = for 20 shocks. Not tested of course, but that is the risk one always has. But that was the best we can do, disassemble original and find the rigt hydraulic seals. We will test them here in Japan now. So in 5 years I can tell you the long term test result ;-)