Hasn't been done much on Nissans, but for that type of general off road tech,
http://www.pirate4x4.com might be a good place to start. Stay away from the Nissan specific forum and go in and tell them you have a Toyota...you'll get a lot better feedback, and there's really not much fundamentally different between the two.
It's a site with a ton of offroad info, and a bunch of idiots scattered in between. If you can cut through the crap, you'll find what you need.