Dynocom dynos are notoriously inaccurate. It's unlikely you're making over 800 and only go higher 5s 60 to 130. My car is very similar to yours and is under 800 and I run in the 4s. If you care for more accurate numbers a dynojet would be your best bet.
Your car should not be pulling 3 degrees with them shut then adding 3 degrees with them open. The borla resonator will be similar to stock. Magnaflow use to make one that was slightly quieter. What you have now will be one of your quietest options.
Yeah I think even if it was a small restriction it would be so minimal it wouldn't be much of a concern. I understand being efficient and looking for every last hp but as I tested plus or minus another 5 or 10 hp or so at 800 hp you're not going to notice. The weight savings if any you'd...
I tested at 12 lbs with a centrifugal. Catless longtubes to a completely stock catback with internal 2 inch neck down then tested a full 3 inch straight through exhaust set up, results were about 25 rwhp at peak rpm (7800). Gains started around 5k on up. Also it was almost 30 pounds less weight...
It's not just about the neck down it's about turbulence. The stamped Xs are turbulent especially at lower rpms because of the exhaust pulses tumbling all around, that's why they are usually quieter as well. A proper sized true X increases velocity as the pulses go through creating slightly more...
A sound clip would be nice. I think the Jones will become a littler louder in about 1000 miles.
The Jones is just a stamped X/H section like the Magnaflow which is the worst version of an X pipe but common for cost reasons, I wish a company made a true resonated x section.
Brushless is definitely the way to go I
I prefer returnless as well but there isn't much innovation anymore. I'm disappointed the companies haven't switched over by now.