I don`t agree with U Bascule.
Some of the cone filters soak up alot of heat, yes.
My reply was considering an original replacement air filter
As for the sound; A matter of taste
As for the power; Assuring an unrestricted air supply is the way forward.
The after marked "sport" filter debate can go one & one & one & does so in every forum.
Should be up to each & one to fit or not.
There good for petrols but I don't see the point in a diesel. As said above fuel is your limiting factor not air. Its the opposite in a petrol(throttle control) thats why you get performance cars with cone filters, 2 stage turbo's, superchargers etc.