I just modified my car by removing the old air filter box and resonator tube and added a brand new K&N cone air filter. I've done some research but haven't found a definite yes or no as to how exactly the resonator tube affects performance and if there are any measureable gains by improving air flow with the cone air filter. By empirical results, it seems to me that when shifitng from 4th to 5th gear the car does not drop in speed at all and has a little more kick at the beginning of 5th gear. Thanks for the responses guys.

~jeff~

p.s. I have a 1994 protege dx SOHC