Who said a "black diamond" over a sachs.........? You're kiddin, right!?
Black diamond clutches are total scrap! All they do is an uprated driven plate, with stupid heavy clamp springs on them, then a cheap remanufacured friction plate! So when you take up drive, it clunks, gives a huge shock through the stock remanufactured friction plate and shock loads the centre of it. After about 5-10k miles, the middle of the friction plate cracks and drops out, meaning no clutch.
I have three, all the same on a mk2 8v making 150hp! None laster over 5k miles, same thing each time! Oh, of course balck diamond customer service accepted their warrnaty claims and sent a new one out, but it dont halp wiht the £200 labour each time!
In the end, they were such crap I put in a stock vw clutch,. no slipping and 15k miles better still perfect.
Be careful of any "uprated" clutch that is only a driven plate with massive clamp springs in, it will muller the centre of the friction plate every time unless friction plate is uprated too.