I have not long ago installed a pioneer AVIC-F40BT. I decided that buying cheap would be costly in the long run. It comes with off road maps too. It was easy to install. Just a bit time consuming to do it properly. I made my own loom to interface with the Nissan loom. The after maket ones are way too long. I made mine only as long as they had to be.

A little snippet.... When you have done all your wiring and are ready to install the unit wrap some thin foam around the plugs. I got a sheet of the stuff from clark rubber for a few pennies. Use some insulation tape to hold the foam on. This will go a long way to prevent any rattles....