Here is a suggestion to kill some chatter problem on the drive shaft.
It is very easy, just remove the set screw (on the cross spider) off and put a collar on the axle to hold the drive shaft pin instead. Top Racing makes the collar for this and it fits perfectly on our axle. But you can also use the collar from our option parts #67731 POM solid axle cup joint. (please see the picture attached)
When you remove the set screw off from the cross spider, the drive shaft spins freer. I would say that the best combo is to use with POM spool drive cup (#67731) and no set screw on drive shaft. The DCJ still runs smoother than this, but it is very close to DCJ feeling.
If you are fighting with chatter problem, i recommend to try this.
Please let me know if you have any questions.
Hope it helps.
Hiro