Life expectancy for daul-mass flywheel ?
 

Does anyone out there know the life expectancy for the Boxster Dual-mass flywheel?

How many miles should you get out of it under normal use? Thanks for your help!

I've heard people saying that they need to be replaced around 100K. When I did my clutch at 90K I used this procedure (http://www.pelicanparts.com/techarticles/Boxster_Tech/44-TRANS-Clutch/DualFlywheelTechBulletin.pdf) and it checked out okay so I decided to risk it.

It really depends on driving style. Mine was shot at 96K but I didn't notice any driving issues. If you do a lot of standing start clutch dumps or rough shifting you can expect it to die young. A smoothly driven car should go 10 yrs or 100K.

100K miles seems nominal. Mine was long gone at 92K.

Mine was completely shot at 90K which means it was probably gone long before that with the previous owner.

How does one know if it's working or not? When it's gone does it make noise, vibrate or are there other tell tail signs? What do you notice with a new one installed on a car with 100K?

Mine has 114,000 miles on it, I changed the clutch at 90K and it seemed fine. I drive the car pretty hard and run a few autocrosses a year. Maybe its shot and I just don't know, its not ratteling and still grabs though. Whats the go to aftermarket option for these things?

Test it:
http://www.pelicanparts.com/techarticles/Boxster_Tech/44-TRANS-Clutch/DualFlywheelTechBulletin.pdf

My old one was not making noise and looked ok on the surface but failed the elasticity test. Rather than drop $800 for a shiny new one I found a low mileage takeoff that was within spec for $150.

On my side, prior to change my flywheel, when driving slow (40-50 mph) & I suddenly accelerate at a changing traffic light (red to green) I had a kind of motor or transmission miss for half a second. I finally discovered that the miss was the result of too much play on the dual mass flywheel. Should be 15mm not more. I had much more then that... After changing the flywheel, no more miss and smooth accelerations.