I ordered this cable harmess:
20 pin OBD II-Adapterkabel Scan My Tesla Model S/X (> 09/2021) (LR + P
Also bought S3XY Buttons which connect on the same car connector and includes a harness.
I ended up mixing the harnesses and use the one which has one cable more in the OBD-connector. Dunno which it is of the two.
SMT works fine, I use a OBD-splitter 1-2 to use both SMT and the S3XY Buttons commander. Works fine.
I had a OBD2 interrupt cable between the harness and the MX+ to be able to power cycle the OBD Link MX+ when the connection was lost which happened fairly often on the M3P I had.
Its currently installed on my MSP but has not been needed even once yet.
If any problem and you do not use a OBDLink MX+ I guess the reason is that the other dongles have a hard time coping with the amount of data sent each second via the dongle.