Yeah I’ve never done it. This is my first actually owned car. I had outdated civics before that weren’t worth customizing.It'd only be a warranty issue if you don't know what you're doing and don't do it properly, and they can prove the hackjob underglow is what caused whatever else to fail. Kinda sounds like you don't know what you're doing.
Amazingly, you appear to live in a state that does not have strong restrictions on Under Body Lighting.Is it feasible to put underbody light kit on a 2017 civic coupe? How would you route the cords into your car? Does wiring them up to your battery void your warranty?