I just wanted to make a post about my lift, vibrations and what worked for me to fix the vibrations.
So, I have a 09 Double cab Sport 4x4 with automatic.
For a lift I have a stage 3 Icon lift. Up front I have the Icons set at 2.25" and the 1.5" aal in the rear.
Right after I installed the lift I had a noticeable vibration around the 5 - 10 mph range that I could feel through the floor board.
I ordered the Carrier Bearing drop kit from Toytec, and this 100% fixed my driveline vibrations. I have no vibrations now and
the truck drives like a dream.
I think the more you lift the rear of the truck, the more noticeable the vibration will be and the more difficult to remedy.
Anyways, thats what worked for me. Cheers.