I didn't use one with that kit, but I think I should have...
I am going to put one on this summer, and yes, I am going to use a 2" spacer.
I haven't had any trouble per se, but I did pull the thing off once, and had to go back and use some serious grade 10.9 bolts on it.. haven't had any trouble since, and I have wheeled the piss out of since then..