Both of mine still going OK on both Renesis and 20B (with 13B turbo rotor housings)
The fiber stuff is probably gone though.

Just had a happy finding on my 20B  RV-8.  I was a little disappointed that it was not quieter since I put a lot more sound proofing in it than the RV-4 has.  The 20B was a little louder in the cockpit than the Renesis.  Happened to try turning the noise canceling off during a flight (in RV-8)  yesterday and found that it made no difference!   Today I discovered that the Bose headset jack for the front seat was defective and was not feeding power to the headset so the noise canceling wasn't working.   Can't wait to try it after I get it fixed.

Tracy