Heat shrink butt connectors as well as heat shrink tubing over those butt connectors is a great idea for sure.got all lights installed and everything works. SUPER BRIGHT little suckers. I'll post pictures here soon. If anyone decides to do this kit, I recommend buying heatshrink to seal up the connections so when you go to put your boat in and you submerge your light, it doesn't screw up your truck when water hits the live wire. all they supply is wire nuts
But the best tip for not having your boat trailer lights affect the tow vehicle lights when submerging is to unplug trailer lights before sinking trailer in water.
Also...since most all trailer light issues are caused by bad grounds...tee'ing into and grounding each trailer light ground wire to the trailer frame where the light mounts to trailer will solve many of the grounding issues.