Did you have the exhaust or listened to it before getting the turbos installed? I have the Fast Intentions TDX with 12" resonators, and it drones in the same region as well. It was bad when I had the Berk HFCs, so I went back to stock. Now it's much bearable, so perhaps you can look into getting the TDX with 18" resonators (what I wanted from the start). I'm only suggesting TDX because it's what I have and tried, so there's not much to compare. What I can tell you is that my gf hated my car and says it sounds like a boat. She's much more tolerable of my car now with the stock cats.
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