there is no muffler? as long as you have a fuel controller thats set right, it should flow better than a stock exhaust. so it shouldn't decrease hp. i have never heard of that exhaust, but i never heard of any of the exhausts on this site except dmc. :lol: but if it is a bad design, it might not make as much hp as a more known exhaust. but it should be better than stock, unless you don't have a controller.
Yes that is a great pipe possibly the best single pipe on the market if you have a built engine, such as bigger valves, cam, high compression piston, or a stroker motor, it will put out gobbs of power.