It would be very easy to replace the clutch, IF Audi sold the parts... but they don't. I've done a few of these and I'm yet to see a "tired" motor, it's always been the clutch slipping.
I fixed mine with violin rosin for about a year and 10k miles ago, still working fine. If it stops working I'll just do it again, it's a 20 minute job after you've done it once
