how often do you run the engine at 5000 RPM ? the only time the intake ever becomes restrictive is above 5000RPM and its not restricted by the filter, instead the throttle body does all the restriction. and since the engine red lines around 5200 and i beilieve thats where they put the rev limiter. the only time those intakes help is if you are running a very agressive cam or a turbo/super charger. save your money, buy some tires.