Just wanted to say I successfully installed the stock Nissan impact sensor on my 2010 SE Crew 4X4. The part number is 999M2-VU000. Works fine. Comes with the wires taps and takes about 30 minutes helped by the excellent clearance under the dash of the Frontier to the wire harness block.
One thing strange was that the Nissan instruction schematics had one of the harnesses upside down compared to what was in my truck. Just look for the correct colored wires as these are correct regardless of being reversed on the drawing. Not sure if previous models are like this or this is just a schematic drawing error someone missed before publishing. I assume it is a simply schematic mistake.