Yes the DM fly will fail at some point, they decided to make the fly from two parts with rubber bushing between, once the rubber bushing goes the fly wheel is scrap.
I fitted a Stage 3 Clutch and aluminium fly to my old ST170 and it transformed the car, pulled like a train in 1st & 2nd and easily knocked a second of the 60 time. With the few mods i had i could get to 60 in under 7 seconds You will get a bit of noise on idle with the clutch pedal up though but it never bothered me and if it bothers you push the clutch in and it goes away.