If you’re in the market for some goodies for your new Ford Mustang – and they’re not from the accessories section of the official Ford brochure – you need to be asking any and all aftermarket businesses questions about ADR compliance.
This is the difference between the wild west and a professionally run operation. And when the sheriff rolls into town, you don’t want to be relying on the cowboys to back you up.
Unfortunately, drilling into the particulars and technical minutiae of ADR compliance, and the different regulations of each state, would potentially fill half an edition of MOTOR, so all we can do is recommend you be a smart cookie and do your research prior to entering the aftermarket to get parts for your ’Stang.

500kW Ford Mustang killed by ADRs
Whatever information you are provided, seek independent, professional advice specific to your state, on how the authorities might regard your powered-up ponycar should you find yourself with red and blue lights in the rear-vision mirror.
It can vary significantly from aftermarket business to aftermarket business. And could be the difference between years of hassle-free enjoyment of your modified Mustang. Or going home in a taxi with a very big headache.

It goes without saying, check all of the fine print of any warranty you sign to make sure you’re not going to be using the car in a fashion that the provider has listed as an exception in clause 6.2.4.
Happy and smart Mustang modifying!