Congrats on your new Challenger! To answer you simply: no, installing headers will not void your Dodge warranty. However, if Dodge determines that your aftermarket headers damaged your Challenger’s systems, your warranty will be voided.
This is typically the case for most limited warranties. While the Magnuson-Moss Warranty Act allows drivers to purchase aftermarket parts for their vehicles without voiding their warranties, car companies are still within their rights to void a warranty if those parts cause damage to the car. It’s therefore always a good idea to consult with a Dodge expert or mechanic before installing any mods on your Challenger.