I had the driveshaft modified to have a longer splined section where it telescopes in and out. This helped SIGNIFICANTLY, and allowed me to drive the car up to 80mph with MUCH less vibration.
After 80mph, the vibration gets bad, but As a daily driver, this was "good enough" to hold me off for the time being, until the school year is over.
It seems that because of the AR5's in and out thrust at the output shaft, the driveshaft needs to be able to accomodate for this plunge. Im guessing this is why the factory Solstice used a CV at the transmission end, and a rubber guibo at the differential flange.
What does this mean?
It looks like it will be necessary to use a plunging CV Joint at the transmission end, and in theory, this SHOULD fix the issue.
The problem is there are no high quality / high performance CV flanges available that fit into the Solstice/Sky AR5 output shaft.
The only brand I have found is Dorman. I am hesistant to use them as they are a standard parts store brand, and I have seen many parts store brand axle CV's fail within 6 months.
Here is a link to the kit, which includes info on the dimensions, spline count, etc.
I do not trust it to last for more than a few months, so I am still looking for a better solution before making any decisions. I am also hesistant to weld a used factory Solstice driveshaft CV, as I don't know what kind of life span to expect from it.
I have emailed DSS and am waiting to see if they can get any high performance CV's for the AR5 output flange.
Fingers crossed that I eventually find a solution for this. Any additional input welcomed
Attached is a picture of my current driveshaft