My experience is that with valves closed, it is no louder than your stock setup. With valves open, different story altogether. I wouldnt have purchased this exhaust without the valves. There is drone inside the cabin only with valves open and only between 1500 and 1900 RPM. You can cruise comfortably on highway with valves open without any drone. Valves closed, no drone at any time. For me, it's exactly what I was looking for. The power tap is not difficult if you have a shop that knows these cars. I opted for the remote control and my shop tapped the cig lighter in the trunk for power. Ive had no issues.
2016 Individual M5
2015 F86 X6M
2015 i3-REX- 2012 Wrangler Unlimited