after so many static tests with prototypes simulation the best filter is k&n rc3870. is the most largest/long possible.
there is a very good difference in power. especially in 2gear very easy wheelie only full trotthle! considering that I am very fat. weight 100kg whitout bike clothing, see video.
I consider that this change is the best solution for goodmore power and big torque at lower cost.
fuel consumption change only whit full trotthle.

I'm planning to do also trotthle body + 2mm but with the original engine and the stage3 not know if I will have improved power. maybe someone could answer me.