Be careful...I read somewhere about another guy who had a lift installed (not a Calmini lift...I forget which one...) To fix the vibration, he had someone from the shop mill a spacer out of billet aluminum, yadda, anyway, they did that, charged him lots of cash for the R & D, and then the spacer and it made the vibration worse. The drive shaft needs to be balanced, and if that spacer isn't part of the balance, it can make it worse overall. If your shop knows what they are doing, they may be able to fix the issue and not have the same problem. The shop the other guy used seemed to be a tad clueless.

The guy added diff/spring shims as was instructed by others on the thread I was following and it fixed it after pulling the spacer. I want to say the lift was a coil over in front and new springs (Alcan?) in back.

I do not disagree with you that the issue may be the slip yoke. I also know that Calmini is working on it and if their timeline is doable, I will wait a tad longer. If it is out there a bit (more than a couple of weeks), I am going to do the drive shaft with a double cardan set up. It will wipe the angle issue out completely and add length to the shaft.

If you do the spacer and it works, share the wealth!!