Would this not be easier? It's slim, you wont even be able to tell that its not hardwired.
Amazon.com : PowerJolt Dual Universal Micro : Vehicle Audio Video Power Adapters : MP3 Players & Accessories
Picked up a 2014 Trail with Entune, Mats, Cargo Bars, and Exhaust tip last week.
MSRP $37,645
Got it for $ 34,698
$ 37k even out the door with title and tags..