[GuidoK]

Yes but sachs now has a new line of clutches. I think they used the 618/765 in the past with a stock pressure plate because sachs didnt make fitting performance clutch plates for those pressure plates (maybe different splined centers). I also wonder if 618 and 765 were originally designed for bmw.
Now they have fitting kits (seperate clutch and pressureplate is also available) in organic and sintered with 22 spline (so for 6 speed boxes) especially for bmw. So with the right thickness and right pin setting.
The organic kit goes to 540+Nm (that is what I use) and the sintered kit goes to 780+Nm which is enough for most applications.
But I think the bigger problem here is that the TS may need a sprung clutch, so both stock and SRE clutches are not suitable.
UUC twin disk is interesting, but he already seems to have an aluminium flywheel?!? Self made?
Way too little info to give good advice on something as complicated as a performance clutch.