When I first had my Gemini installed, I loved it. It sounded aggressive and loud, but with stock cats it was very, very livable everyday. When I got my ART Pipes installed last year, the exhaust note developed a very noticeable boomy drone under throttle at 2000RPM to 2500RPM mark once the car and exhaust were hot. I personally hate excessive exhaust noises when a car is hardly moving. If I'm trying to gain just a little bit of speed, I don't want to hear "baaaaaaaaaaaw" from the back of the car.
So, I decided to get clever. When Invidia sent me replacement flex sections last year, I was able to keep the original and defective ones. I didn't throw them out, because I thought perhaps I could use the piping for something else - which I did, the resonators specifically. So I looked underneath the car to see where I could weld in those resonators and it was pretty clear where they'd go.
I asked Real Auto to do the job for me, so they had cut out a section of piping right behind the muffler and welded in the resonators in their place instead. Clearance is perfect, there are no odd noises or anything strange. Just resonators doing their job at eliminating unwanted noise, cleaning up the sound of the exhaust, and completely eliminating the drone with no drawbacks.
The overall tone of the exhaust now is quieter than before, but definitely better than the non-existant sound the OEM exhaust made. This sounds more like the factory tone of the 350Z or even a slightly louder G37 - both cars which sound better from the factory than our 370Zs. That was the goal I was hoping to achieve, and I did. You can see in the pics below where the new resonators are (right after the x-pipe) and where the flex section resonators are (right before the x-pipe):
