Front Diff Moaning
 

Guys, set of new p zeros fitted today. I noticed a grinding and binding sound or like LSD slipping as I moved off with the steering at the limit. Could it just need a diff fluid change or is another Quattro monster job? Best Steve

If it's the noise I think you mean, I've had it a few times on the D2s I've owned. D3s might be different but in my case it has always turned out to be worn suspension bushes, despite sounding/feeling more serious.

Diff Groans
 

I've been reading other posts, it appears to be 'normal' Quattro diff groans. The new tyres are very grippy. All bushings/ arms are good.

If it is the Quattro binding? It only happens while power is being put down or decelerating in a manually selected low gear.
It means the Quattro is working but if the effect has increased over time, it may be time for a centre diff fluid change. The correct fluid contains a Sturaco friction modifier that reduces this effect but as the additive depletes, it gets harsher.