IPD catback exhaust experience

[brenglxc70]

So I bought one early this year because it was on sale (as it is again now) for a very good price and was much cheaper than replacing the entire stock system. My stock exhaust was literally rusting off the car and had to be replaced. It was so rusty that I didn't even need a wrench to remove it, when I unhooked the hangers and pulled on it, it fell off in the garage floor. So, the IPD system...

Pros: Excellent fit and finish. I had to cut out the rear plastic bumper valence a little to fit the V70R style exhaust tips on the XC70, but otherwise it fit perfectly. Sounds amazing OUTSIDE the car. Looks great.

Con: On a wagon it creates an unbearable ear-bleeding drone inside in the car that renders it undriveable without ear plugs. It will literally give you an instant migraine. I am not a curmudgeon either, I have owned quite a few loud muscle cars in my time that would set off nearby car alarms and even required ear plugs to drive long distances. This was much worse than any of those, despite being attached to an engine less than half the size with less than half the power. Upon doing some investigation I learned that a smaller displacement engine actually has a lower frequency exhaust resonance than a larger engine. Who knew?!?! So now I had a car with a $600 sweet looking stainless exhaust that I couldn't stand to drive.
Further investigation led me to get a frequency analyzer app for my phone, figure out the worst frequency range, and fabricate a 1/4 wave tube out of pieces of the old exhaust (the original tubing was stainless and was not rusted, the rust was at the connector and the muffler). Although quite difficult (and impossible if you do not have a welder) this actually worked somewhat and made the car tolerable to drive, particularly on the highway where RPMs get out of the bad resonance range. BUT there is STILL an uncomfortable very low frequency drone, too low to be attenuated by the 1/4 wave tube, and carrying passengers in the backseat is not an option.

So now I'm faced with either removing the entire thing and spending twice as much again for a new factory system, or attempting to swap out the IPD muffler with a quieter muffler to try and further attenuate the low frequency drone. I am not sure that will actually work though though because the resonance may be more related to the 3" exhaust tube and such a low frequency has a very long wavelength that is not easily cancelled by a little metal box. All in all a very frustrating experience!