what can I say, my car has done about 80k miles total with about 20k miles boosted with pretty hard (hard but correct) use.
There have been 2 times that I pushed the torque through the clutch capacity, and that is with very hard shifting where full power is applied when the clutch is still not 100% engaged. The way NOT to do it so to speak (sometimes even I make a slipup....)
For the rest it's still just fine.
As long as the clutch holds on full torque, it's fine. There's no other parameter.
I don't know what you mean by dragging. If you release the clutch after upshift it's supposed to slow down the revs to the gear-matched amount.
The hydraulic clutch is self adjusting.
And certainly when the TS isn't planning on cams&headers&elevated boost (and knows how to shift; adding boost is an easy way to destroy your clutch faster) it will be fine.
I run with 90Nm more torque than a ts2 is rated for (according to ESS) with the 2.5i with the same clutch plate. For me that says enough.
Budgetting for a new clutch is something you can advise for every car in every condition other than brand new. It is a wear item heavily subjected to the way it is driven. Spirited driving wears it more than normal shifting on lower revs etc.
Also an uprated clutch can be very influential on the driveability. This car is a daily driver, and no one wants to be stuck in traffic with a racing clutch
From that pov alone I wouldn't advise an uprated clutch (unless you can test the product on forehand in an identical vehicle)
(but from that pov I also wouldn't advise tuning/adding boost)
The TS should budget in things that are more affected on power. Tyres, but maybe also some bushings etc, maybe a new MAF. Adding power will always speed up wear in numerous ways. Not that he needs an uprated clutch for that; there is no relation between the wear/life and torque capability of an uprated clutch. Uprated clutches can handle more torque before slipping, they don't automatically have a longer life span. They will however eat faster through your flywheel.