Don’t modify the exhaust on your mopar
From the article, the manufacturer has a different story:
"He says the mid-muffler and entire emissions system are stock. But this is where things start to get confusing. You see, Dodge says this isn’t about the mid-muffler. Dodge says, “The warranty claim was rejected after a Stellantis Calibration Engineer ran Powertrain Control Module (PCM) diagnostics and confirmed that the vehicle’s PCM was tampered with and contained non-factory software.” A spokesperson added, “I haven’t seen anything on our end regarding mufflers (ie not the issue).”"
Anyhow, it sounds to me like the dealer is looking for any excuse to avoid providing repairs (typical). Hope their attorney is familiar with Magnuson-Moss. But if the owner reflashed the ECU with an aftermarket tune, he's probably SOL...