The DeeZee Truck Bed Mat # DZ86965 is made of 3/8 inch thick Nyracord. It's designed to hold up to being abused.
If you watch the video I've linked, around the 2:50 mark you'll see bricks dropped into the truck bed to show you how the mat is durable and protects the truck. view full answer...
You are correct that the material under the cover - the panels - of the Lomax Hard Tonneau Cover # LOM45FR are made of aluminum.
The Xceed is a fit for your 2014 Nissan Frontier with a 5 foot bed, and is a simple installation as it just clamps onto your truck's bed rails. It will do a perfect job of offering your Frontier's bed protection will also improving its aerodynamics to resist drag and improve your miles per gallon.
I have added a link below to a video review for you to check... view full answer...
I recommend taking a look at the Malone TradeSport Truck Bed Ladder Rack w/ Load Stops - Aluminum - 800 lbs # MAL55VR. This is a very affordable setup that clamps onto the bed rails of your 2018 Nissan Frontier, as long as it is crew cab 5 or 6 foot bed without utili-track system, or if it is king cab 6 foot bed without utili-track system.
T-slot channels are integrated into the crossbars of this ladder rack, making it very easy to install a wide array of accessories like kayak carriers... view full answer...
The Quick Splices - Self-Stripping Connector - Closed Port - 14-16-18 Gauge - Blue - Qty 1 # SWC502905-1 is weather proof and water tight, but not waterproof. To further assist I recommend adding dielectric grease # LT37534 to further protect the splice from water and debris. As long as the grease remains as a protective layer, you won't have issues but it isn't recommended to submerge. If you are looking for a submersible connection, I recommend the Deka Heat Shrink Butt Connector -... view full answer...