i would like to clarify something here before this gets blown out of proportion and blame is placed in the wrong area. theres NO evidence that the wavetrac caused this or any other ring or diff failure. the ring and pinion failed which are in no way part of the wavetrac design or part. these are oem parts that had thousands of miles on them.
a cursory look at the wavetrac shows no obvious damage but certainly the unit needs to be torn down and inspected closely. the pinion gear however looks like a catastrophic failure occured whether improper shimming or a metal failure to to excess torque from the driveline has yet to be determined to be the cause .

afaik there hasnt been a single failure of the wavetrac unit itself. these units can handle upwards of 1000 hp and are a well built unit.

and no the c63 diff wont fit in this platform . the long term answer imo would be case hardened gears which would have to be custom made