That is very cool. I still have my stock pipes in a box. I was thinking
about opening them up but, now after seeing whats inside
I wouldn't wast my time. I took every thing out of my TOR's
here is a render I did of whats inside the TOR's
and an actual pic of the insides.
And yes, they make some noise. I think they sound great.
Here is the render I drew
and here is the actual pic of the insides
All there is ,is a piece of pipe about 6" long and a piece of perforated pipe about 12" long then a piece of pipe about 3"
and there is insulation packed around the perforated piece