[1320B4U]

Then as a consumer you would sue the company of the fake 'dot' approved taillights b/c they mislead the consumer/dubious business practices. If it is stamped w/dot and there is paperwork stating this (directions stamped w/dot approval) this would hold up in court. In getting dot approval there should be rigorous tests done to be certified which are available in writing for that specific unit, although you winning that case will be directly related to how much $ you have on fighting this to the end.

Either way if you have something that isn't 100% stock on a vehicle be prepared to potentially be harassed. Its just an opportunity for law enforcement to pull you over. Being polite and courteous goes a long way when talking to the cop.