I can tell you I have probably installed 500 sets of torque cones in my lifetime on Hardly Davidson bikes with straight or drag pipes after the owners complained of power losses. Not the best solution, but after some fool pays $700 for exhaust that costs him 5 of his precious 80hp, they usually don't want to spend much more to fix it. This is in the same category as straight velocity stack intakes. They look cool but function like shit because the air is pulled back out of the carb as it passes over the stack. I've swapped out about 500 of those too.
Not to mention people around you will hate riding next to you.