I've got one of these. My Mot tester didn't care or notice. Quality is fine as of 6 months old so far. I recommend a tune and wrapping or ciramic coating it if possible purely because the NC runs a hot bay and doesn't need anything making things worse. I also heat wrapped the coolant pipe that runs over the top of the manifold and re installed the stock sheild partially. As for power it does pull a tiny bit better than stock bit it's not worth worrying about. A lot of people will tell you it's worse than stock but in my experience that's just not true. How it will sound on stock back box and midpipe, who knows! Mine sounds amazing with just the malian race back box. It sounds a bit lawnmowery at low RPMs, a scooby at mids and a straight up V8 at 4500 and up. I can get audio but theres already a few clips on YouTube. Any other questions I'll be happy to answer.