Savage FLM Extended ARM kit

I recently installed the FLM extended arm kit on a FLUX, and the driveshafts are slightly short of a perfect fit. They aren't spinning around perfectly - there's some offset while they are spinning, and sometimes it locks up in the HUB or outdrive (Happens mostly in the front I believe.)

Now, I could probably fix this with O-rings or some sort of spacers in each drive cup, but I expected these driveshafts to be a perfect fit for the arms they came with. What's up with that? Anyone else experienced this?

If there aren't any quick, easy fixes for this, I would like to go with a CVD kit. Are there any suitable kits for the Flux power?