Your rig shouldn't be down for a few days just because of relocating some hangers... <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

When I did mine, I got everything ready (clamped hangers on and test-fitted springs in my driveway to determine hanger location), and the took my rig over to OPP's house and he welded the hangers on for me. The only reason it took more than a half hour or so was because we had to remove the gas tank to weld the inside of the pass. side hanger.

Then I drove home and bolted everything up. <img border="0" title="" alt="[Big Grin]" src="images/icons/grin.gif" />

And yes, you need new rear shackles of some sort (no matter what springs you use).