Personally i have experience with the Sachs uprated with single mass flywheel.
I won't recommend it as it can't shift at high revs and can't take fast shifts.
We have one "of the gang" running Helix, he's not that pleased with that one either.
We have one that have had southbend stage 4 clutchpack, not very happy with that either. (Southbend is Sachs clutches)
DxD clutches is the same as Southbend which is the same as Sachs.
So i will try Clutchmaster next, haven't heard any bad things about them yet. From what i gather they make their own clutches.