Vibration with WSI HD Leaf Springs

I recently installed WSI HD Leaf springs on my 14 Raptor with about 38k mls. I now get a vibration from 5 to 25mph. It goes away above that.
any thoughts or suggestions would be greatly appreciated. Other then that the truck rides awesome and tows my trailer so much better than stock. I thought maybe the vibration when go away once everything settled in, but its only gotten marginally better.

Could be pinion angle. If the springs raised the ride height it may have the driveshaft at a different angle. Most Driveline shops can measure it for you. If it is out of specs the rear axle can have a wedge installed to bring back the proper angle.