Tuned length is a big thing.
When the exhaust gases come out in the firing order, if the piping is the same lengths it means that the "sausages" if you will, of gases will make a long line of gases when they connect to push on the turbo wheel or exit the exhaust (n/a engine) this means no kinetic engergy from the gas is wasted when the gases impact and is put towards spinning the wheel or exiting.
The reason its not traingle piping and IS normal sircle picing is so it runs smoothly through thus wasting the least amount of energy. or so it can exit the fastest. Traingle section doesnt flow well
