Tested it today. I was eyeballing the distance and angles based on what I remembered from reading the SAE J1169/J1492 testing specifications, but I think I got it close. I also only ran the test once on the left-hand exhaust outlet, when an actual noise level inspection test would run it at least twice on
each outlet, average the results from each outlet, then take the value for whichever side is louder.
The meter recorded 103 dB. :/
Now, there are a couple of factors that
may help me out on an actual test. First, again, I was eyeballing it. I may have had the meter too close, or less than 45° off the axis of the exhaust outlet. Second, in addition to this exhaust, I've also got the Perrin 2.5" Cold-Air Intake and the Perrin inlet tube; noise-wise, these mainly affect the sound up front, but getting more, cooler air into the engine
can affect the exhaust noise a little. I'd have to swap back to the stock intake to get it registered in California anyway (or switch to another intake I found that has a CARB E.O. approval sticker...but I've already got the stock one, no sense shelling out more money
yet) which would hopefully drop the noise a bit. Would it make 8 dB of difference? Dunno, but it might.