The exhaust cans on the sides have always been Bosal. There used to be a Y-pipe instead of a resonator in the center, but anyone that experienced the road show cars knows just how loud those were, so the center resonator was created. In fact, 2 weeks-ish after I started at Fisker HQ, I was on the team that designed the first one. Anyway, a number of different versions were mocked up and tested, and Stillen was given the account to build them. On a side note, and this I heard second-hand, but I was told that Bosal initially told Fisker that putting a resonator there couldn't be done. The motortrend article is probably going by the older info when it was just a y-pipe and cans, since the very first few cars were built with Y-pipes. There were a few of us technicians that were cycled in and out at the port in NJ mainly to install the resonators onto the cars as they came in. I was part of that port work.
So, fast forward some months. The Stillen exhausts started breaking on the engineering cars. Repeatedly. 4 Bosal prototypes were brought in, and the NVH team wired up a car with microphones all over the interior and tested each one. There was also 2 passengers in the car, one in the front and one in the back to give a subjective thought on each one. This I know for sure, because I was the one that had to uninstall and reinstall the next prototype whenever the car came back from the test. I also took the passengers on at least 2 of the road tests.
Ultimately, one of the Bosal prototypes was chosen and production was started after that. This was some time after the car had already hit production though, so LOTS of cars were built with the old Stillens, thus there are still plenty out there. Bosal was quick to figure out that their arms couldn't handle the stress and would break, and added the reinforcement welds. Only a few slipped through without the extra welds.
The Bosal is hands down a better product. I've only seen one car with an exhaust part break that had the Bosal installed, though it wasn't part of the actual exhaust. It was the bracket that held the Catalytic Converter. This is definitely a part I'd recommend changing out.