Why is that some tuned pipes have 2 chambers and the others got 3? Is this to muffle the sound? How does these 2 compare? I mean which one will give more power or mileage? I m asking this because im in the market of buying tuned pipe for my future .21 on road engine. I m still to decide either Nova 359 Tuned or Picco P9R. I ve been advice to use Sirio pipes with whatever eng I will choose.

Thanks!