Installed Wunderladen a week ago and picked up my friend. He didn't notice that I had replaced my RMM until I told him. There is very little NVH even with the AC on full blast. I'm really happy with this RMM.
I just installed this exhaust over the weekend. I see that you're in NC. If you're in the Raleigh area and interested in hearing it in person, I'm down to meet up. Right now, the valve is set to open so it's louder than it should be in normal driving. Waiting for my tuner to readjust some settings.
Have you tried disabling the P0139 error in the DTC’s section of the misc. area of the calibration window and then uploading the calibration to the ECU?