I first cracked mine and didnt know for a year. It made the knock sensor upset and was reducing ign timing which means losing power for almost a year before I blew the front transmission seal/bearing. No one was able to diagnose the lost of power at the time and why the ign timing was lowering this much.
Once the new transmission was installed the timing went back where it should be and gaining about 30+whp in the top end.
This second flex plate didnt survived 5000kms as I pulled the 7AT to swap in a 6MT.
In my opinion the first mod on the 7AT should be the flexplate ! then an oil cooler if doing agressive track days.
edit :
the picture from 2011 on the dyno fully tuned but with a cracked flywheel. we had no control and spend nearly a complete year to figure out what was going on ,, almost traded the Z for an EVO X.
