There seems to be an issue about what drone is and the design of our exhaust system. Also not sure why the Dinan Exhaust is being brought up in a thread titled "AA Exhaust"...
Our system was designed from scratch after taking a look at the stock system. The stock system uses a large pan, has a few bends in the pipe with a few "crushed parts" to fit properly and is also heavy. The stock exhaust also has NCC (noise cancellation chambers) inside.
The NCC's are there to absorb drone without being in the way of the exhaust system or to really affect flow, that way it does not effect power, they work a bit differently than just adding a resonator in the pipe.
As stated the stock system has NCC's inside. So we decided to create a system using larger pipes for easier/better flow (for better top end performance) with a straighter path (less bends and no crushed parts ). Then we decided to use the NCC's but to save weight we decided not to insert them into the muffler's, the best way to to incorporate them back into the system is to put them on the outside in order to save weight.
The finished product is our system, it provides a beautiful sound at wide open, no drone, and a very nice sound during part throttle (cruising). Basically I can speak on my cell phone on speaker phone in an E9X M3 with our entire system and speak clearly with no issues; be it resonance or drone.
It has been stated earlier in this thread that all M3's stock or modified (unless it has our software) will sound different after a cold start. That has nothing to do with the exhaust, it is due to BMW requiring the M3's to run lean at idle to heat up the cats to go back down to 0 emissions faster. It was the same on the E46 models as well.
p.s. Ryan only provide a dictionary like explanation on "drone" to help give the community a better understanding of what it is. Nothing else.