If you take the silencer off a gun, does it add more gunpowder to the cartridge? No... Just makes it louder... Studies have shown that the amount restriction needed to decrease the performance of an engine, are so substantial that of the resistance were to be placed on the air filter, the air filter would get sucked out of place... A small piece of plastic isn't going to do much...
Cold air intakes on most engines do nothing but look cool, and infact, a lot of them actually increase the temperature of the intake, vs stock... The temperature will make a MUCH more noticeable difference in your fuel economy than the power you can feel, and there will be a greater impact on your fuel economy from tank to tank purely from atmospheric pressure, humidity, driving habits and even traffic conditions...
If you want to modify your intake to some functional purpose, take a look at my build thread at the inner fender snorkel I built, it routes the intake away from where water will be while wheeling
Sent from somewhere naughty!