[2007Mazda3i]

I bought a 07 Mazda 3i with these mods made to it (stock breather with K&N filter, 60 mm throttle body in place of the stock 55 mm, 2.5-inch cat back exhaust system with a through muffler in it). Would a 4-2-1 header bring me more torque in the low to mead of its 2.0-liter engine?

Thank you for your time,
Daniel

 

[SizeableFowl]

K&N isn't going to produce significant or noticeable amounts of power, a more complex header could, in theory, increase power across the rpm band but you'd need a properly engineered unit.