Bad Drive Line Vibration

Supershafts
Using a local shop for the balance only. They could only run it up to 3800, although the counter guy told me 5000 was no problem. I really want to see it run at 6000. They did add a small amount of weight to the front. The shop before them removed the weight from the front. Sounds all f'd up to me. No further than when I started this post. I'll install the shaft tomorrow, measure angles and see what happens. This time I am going to measure side to side offsets. I might as well throw more variables in the equation.