Out in hellcat a few times over the past week . It runs good after recall. How ever little less snap krackle and pop when down shifting slowly to a stop. It still pops a little just not as much. But I notice down shifting from 4 to 3rd i get some pops that i didnt notice before sounds good. Just not as krackly coming to that stop. I talked to a guy today who under stands tuning and downloading. He thinks cats are probably exactly the same as original ones and the flash was all about new o2 sensors he believes the car had a leaner fuel and know they richened it which keeps cats cooler or not as hot which makes them stay together and better emissions. And thats why less sharpe snap krackle and pop . Again not detuned performance wise.This is what I am referring to......
We will update this forum page soon on what our internal sources say about the sound.
I understand and was not referring to the effects on exhaust.