We'll publish more as we get these production runs tested to be sure, but on all of our prototypes, the mufflers were within +/-0.5 dB (sometimes louder, sometimes quieter, depending on the tester/day/conditions) than stock using the DNR Test (brake applied, hold 4000 RPMs, record dB from 13.5 feet from vehicle, 4 feet high). At WOT, the mufflers were consistently about 1dB louder than stock. The muffler passed the DNR test (requires 88dB or less). To be fair, let's call the stock muffler 79.3 dB and the Reactor muffler 79.8 dB, so yes, slightly louder.
If it's a frame of reference, we've tested other quiet/trail mufflers in the past, that usually registered around +4 to +6 dB,
We'll get a video shot and publish the final data here in a bit. I mostly just wanted to let you know it's very similar in the amount of noise, if not slightly louder. You do notice the sound gets a lot more defined. The OEM muffler has a very "blurry" sound, whereas this muffler is much more crisp.
Hope that helps you make a decision!