wrong
i took everything off and actually it did better, way back in 02 or 03
cant remember the numbers but it did improve
if you look at how emmissions work you will see that exhaust gas recirculates through the intake manifold and heating up the air that your shinny new cold air intake swollowed, and incase that didnt bring the air temp up to 100*F there is a hot water line that goes through the throttle body and another one that goes through the intake plenum
get rid of all that shit, depending on how good and healthy your motor is you might feel a difference ,but realistickly you only gain about 1 or 2 horses/torque and your gas milage might get better or the same depending on how you drive your car