Alright all! Update, several weeks in the making. I have finally found a pretty good balance of sound and minimal in-cabin drone. At this point, I'm really not touching it again... I recently tried a Corsa Pro-series muffler, added to my existing system. This was to replace the CGS muffler that was on the vehicle from a previous cat-back kit. I can say that while the low idle sounds was fantastic and the overall drone was minimal, I really really didn't like the cold startup volume and the heavy throttle sound. It had a great tune, but was super loud. Way louder than I was okay with. So unfortunately, that was a waste of some good money, more on that in a few.
However, once I realized the Corsa muffler was actually a step back, I took a hard look at the stock exhaust layout. And realized there might be something to Ford's use of the large resonator towards the end of the exhaust. So I purchased a Corsa Pro-Series resonator, part number PKM2009. And while this is only really rated for 2-3 Db drop in SPL, this far back in the exhaust system I think it is more than that. By the time the exhaust gets that far back, it's lost some of it's pressure, resonance, and even heat. So my exhaust guys swapped the Corsa muffler for the CSG muffler, and put the Corsa resonator right at the back near the tip, and it actually sounds a lot better. Cold start, warm start, idle, heavy acceleration, etc. Very little drone at all, definitely a healthy volume but low rice-burner effect. So at this stage, here's what I've got from front to back:
SPD Turbo Adapters - SPD downpipes - SPD Stage 2 resonator - CGS muffler - Corsa Pro-Series resonator.
And to be clear, I didn't just use my ears to assess the volume. Going from the CSG to the Corsa muffler resulted in roughly 4-6 Db external increase and about 2-4 Db internal increase depending on cold start, acceleration, etc. Doesn't seem like much, but it's a lot when it's already uncomfortable. Going back to CSG and with the Corsa resonator, it's roughly 3-5 Db less in all situations and smoother during acceleration, doesn't sound as Rice-burner-y.
To be clear, I've tried numerous packages, including the Magnaflow. However, here is something interesting, my exhaust shop typically swears by Magnaflow, except on EcoBoosts. But his magnaflow rep recently brought in a flyer for a new magnaflow product that is supposed to specifically help with turbo exhaust systems like the Ecoboost. I wasn't going to go down this path at this point, but just so others know about it, would love to know if anyone decides to try it. It's the xMOD product that has this really funky muffler with two outputs, one which you put a resonance can on:
https://www.magnaflow.com/pages/xmod-series-universal-performance-mufflers.
Final aft product attached. Oh and if anyone wants it for another vehicle, I have a Corsa Pro-Series muffler part number CP300CT Offset/Center muffler, used for about 2 weeks available. Happy to take 2/3rds what I paid for it, in perfect shape. 3" in and out.
