One thing you'll want to be careful of is that the dash opening in your Pathfinder is probably not big enough for the empeg. According to Crutchfield, your Nissan dash is J-DIN size and the Empeg is made for an E-DIN sized dash. This means that you will probably need to trim your dash bezel. For more info, look at the section titled DIN bay size: here and in this thread. I've done installs in Mitsubishis, Nissans, and Toyotas and all needed some dash modification. Please feel free to ask if you need suggestions.

The biggest tip there is using a flat file to straighten your cuts. Definitely works the best.

The second gotcha will be that depending on your dash, you may have to mount the sled to the metal radio bracket with low profile screws or bolts. Tony Fabris has a good picture of this here. Be aware that when you choose the spot for these screws or bolts, make sure that they do not collide with the screws on the side of the empeg when you are inserting or removing the player.