I had my new, smaller tips installed on the car today (63 inlet to 105x75 outlet) and wow, they really make a huge difference to the sound inside. Driving back from the shop, it was quite a bit quieter inside and I didn't hear anything I would describe as drone, and nothing that impacted the quality of the audio system (which the MBRP on its own certainly could). At the same time, when accelerating hard it still sounds aggressive, and the burbles and gurgles are exactly the same. I highly, highly recommend getting some tips installed!