So we don't have VINs or pictures... but would this be the first documented case of a #8 craptastrophe on an un-tuned car?

Could the lack of a cat with that off-road X-pipe somehow mess up a sensor and cause the calibration to change?

 

It "shouldn't" considering that the primary job of the post catalytic converter oxygen sensors are simply to make sure that cat is functioning.

That's not to say differences in back pressure or scavenging effects couldn't cause an issue. with wide band o2's used for fuel metering though, along with the fuel adaptability, the pcm should be able to account for that with relative ease.

I would think if it was even remotely possible, Ford probably would have looked closer in to the case for a possible warranty claim denial.