Ironically I have been taking to them as well. As JMZ says they only make a dual-inlet/Dual-outlet muffler in their X-pipe style. Since Bill V is of the opinion thats not good for our motors......that kind of sucks. "Progress." I hate it when companies take a perfectly good product, and change it for the sake of changing it. Probably did it as they use those resonators, and those X-pipes on lots of different exhausts, so it streamlines production speed and reduced costs. I do love my Fabspeed RSR system on my 3.2, that I put on it in 2015.
They want just under $2,000 for that setup, and they the told me it's only "slightly louder than the old suitcase style muffler."
Muffler looks like this one. This picture has cats up top and resonators on the bottom of the X I believe. A non-cat system would have resonators top and bottom. To my eye, and for my purposes (less noise), it seems like they could have a lot longer resonators, especially on the bottom....for the 964 and 3.2 style outlets. That would make the exhaust more quiet for sure.
They also said the 3.0, 3.2, and 3.6 RSR suitcase mufflers were all the same size and same size inlet and outlet pipes. Interesting.