That's correct. Most of the aftermarket mods are listed as "off-road" use only. A way that an aftermarket part will void your Lexus factory warranty if a Lexus service dept. deems that the cause of the fault/failure is caused by your aftermarket parts. Some dealerships will turn away some cars with modifications as it is on a case by case basis. Some dealerships are mod friendly, some aren't. It's to their discretion if they will work on your car with aftermarket mods or not.