I've bought the lighted door sills, and opted not to install them due to where the wire splicing is required. Ive already had to splice wires to install the front/rear lighted logo's.
Tesla will fight against repairing anything that has even been touched by an aftermarket product. Granted the law says they can only refuse if its proven the aftermarket product caused the issue. That being said, its a long hard fight, and is it worth it for a couple of lights? But hopefully you can install them and never have an issue.
(Tesla almost didnt replace my front bumper clips because i had a carbon fiber DECAL on my bumper) just sayin.