exhaust drone/harmonic resonance

On the LX cars, some have a Factory X and some don't (they look like they so, but the one of the tubes is not cut) The system I have on my Magnum doesn't have an X or H. On my Dart I have an X and Warlock Mufflers, it sounds good, but I haven't driven the car, it will get tags and INS this summer and i will find out.

There are some header inserts you could put in the tailpipe/tip to help.