I run a independent lambo specialist workshop in london also a highly trained engineer. I've replaced poorly manufactured kevlar/upgrade clutches and all because they are unreliable, unpredictable, vibrations are bad in some cases(mainly on murcies) and I have always replaced with genuine balanced assemblies from Lamborghini. The clutch kits come with a certification of testing and calibration. In all clutch jobs I always also replace the release bearing, sleeve if worn and also flush out the egear system prior to final bleeding and purging, so far no problems at all even with twin turbo gallardos iv' built using the superleggera clutch kits, no issues.
I have installed 2 kevlar clutches in my manual murcie when i owned it and both times the clutch was unreliable, unpredictable and vibrations were the biggest problem, in the end the third clutch was OEM stock and all the problems went away. Removing engine and transmisison is no joke when its down to re manufactured parts, There is a reason why lamborghini only sell a fully balanced assembly. Just replaced an Aventador clutch, no issues!
In my opinion the clutch wear is dependent on how the car is driven, clutch temperature, take off technique and slow speed maneuvering such as parking etc. Kevlar clutches need a special technique to wear in and bed in, they will burn out easy if the bedding in procedure is not followed, this doesnt always result in slipping clutch, the friction materials can get cooked and not grip properly and kvelar is more sensitive than stock clutch for bedding in.
Agree with Hi Tech on ring gear balancing not being a main factor, the ring gear is a finely machined part and very accurate, balancing and vibrations are not a concern from the ring gear itself. The OEM clutch kits come balanced with a mark/line to make the flywheel position to the cover plate position match and the 2 parts are perfectly balanced if installed correctly. Again a bedding in procedure is to be followed and adjusments to PIS need to be made to get the enagement smooth and jerk free. PIS adjustments are essential on both preLP and Lp cars including murcie.
Egear cars are sensitive to clutch take up engagement. Some upgrade clutches have very strong springs and make the final take up harsh or jerky especially at slow speeds and stop start traffic situations , the E gear system is very good and reliable if its serviced and setup correctly but at the same time its operated by PWM signals
which control the clutch control solenoids. This is also a factor with stronger springed clutches where the egear cannot always adapt the engagement. The egear system relies on friction/slip ratio to determine clutch engagement moments between engine revolutions, stall threshold rpm and also transmission rpm signals, all these rpm signals let the egear know when and how to adapt engine rpm and when release the clutch, so if the friction material and spring pressure changes so does the engagement factor!
It seems there is either a clutch issue or release bearing issue, or both with the car in question. Only way to find out is to remove and start again and replace with known good parts, but this time check out all the components involved! highly recommend oem part and a proper setup before and after bedding in and again after 500 miles