Well, I haven't done the whole swap out, but I know you have to have some way to support the tranny while you drop the crossmember to put in the lowering spacers. So if you have that figured out, you're half way there. THen you just have to go do it.
But really, I had them for a while, then when I went to my new crossmember when I did longarms, I took them out, and didn't notice much difference. Oh, and I have not done a SYE kit yet, so you know. Although that is what I would recommend, instead of the transfer case lowering kit.