If your on,y giving it a 2" lift then No caster correction will be needed. I would wait to drive it before committing to caster correction. If you can retain the Nissan rubber bushes they are much better.
Plate are crazy and drop boxes are my choice but really only come into play from 3". And Yes, Drop Boxes are markedly better that correction bushes or plates.
I run drop boxes on both my GQ and my GUIV and they are awesome.

