[Perfectlap]

I have the Fabspeed (+headers). Very very loud at 6,000+ RPM. Between 3-4K RPM the drone is pretty bad but with the top down, especially with city driving, it's not an issue. With top up on the highway it's awful.... but not nearly as bad as when I installed a Racing Beat exhaust on a previous Miata. That cabin is as loud as you can get without adding yet another high decibel soundtrack. One time on the long drive to a track we actually wore our audio headgear to drown out the sound. That must have looked funny viewed from another car.
If the drone gets too bad you migh consider welding the OEM muffler to the rest of the BB setup.