The Burns Stainless NHB exhaust gave solid gains in HP and torque over a wide rpm range for good gains under the curve. The exhaust is 50% lighter than stock to boot, taking a lot of weight from the far end of the car, reducing the polar moment of inertia. The weight lost would be worth the price of purchase to some people alone!
When driving on the street, the exhaust is fairly quiet at part throttle. However, there is a drone at 2500 rpm and another at 3500 rpm. Some people may find this annoying. We didn't think it was bad, but other people have noticed and commented on it. At wide open throttle the exhaust is definitely louder, reminiscent of a Porsche Cup car. It is not extremely loud but more than stock for sure.
The gains in power are noticeable to the seat of the pants above 3000 rpm with the car feeling more eager to rev.
Overall we were pretty impressed with the Burns Stainless NHB exhaust and we hope they will look at other Porsche applications soon, like the 911 models!