Also, when I assemble the bushings on the bolts that they gave me, there is barely enough room to thread the nut on. This is even without the spring plate brackets... if I put them on I don't think I'll be able to thread it! Am I supposed to compress these bushings, or get longer bolts?

I already had to change one thing: they gave me two right hand brackets, but instead of asking for a new one and having to wait 2 weeks, I just cut it, flipped and welded it back.
I'm already having a hell of a time with the front bar... I put it on the top of the trailing arms to save ground clearance, took me hours to get the clamps on... but now it rubs on the body and beam at different points of travel. Yarg! Guess I'll have to pull it off and put it under the arms. My bottom arms are horizontal so it shouldn't be too bad, but talk about a heartbreaker.