Cut, solder and use heat shrink tubing with the type that has glue inside that seals/waterproofs with a heat gun. It’s the only way I do wiring on my rigs. I’m not taking any chances on water getting inside, I hate troubleshooting crappy wiring jobs that let water intrude. I’ve done a ton of electrical modifications over the years and mine have never failed.Yes, they did plug right in with no taping or cutting anything. However, I'm not running them as fogs, I am running them as driving lights, so I need to modify the wiring so they'll come on with the high beams.
As I mentioned above, I'm not a fan of "piercing" modifications like Scotch-loks, so I'm not going with the Fleece unit.