wow everyone here seems really helpful. But in all seriousness, probly as was said around 4-5. But the hp gain isn't what you should look for. Depending on the age of your car, it could actually help with your gas mileage. I swapped out the one on my 240, and got about 2 mpg better. hwy and city. The intake doesn't add enough hp or torque to worry about, but if you keep on working with the engine, upgrading your intake, injectors, hotter sparking spark plugs, and other mods is really the only way that you can feel what your intake is doing for your car. It will however drop the tone in your exhaust. lol If that helps great, and your welcome, if not then sorry.

 

ya, i was wonderin about the intake and how much of a change it would make to change the stock one, since the computers already controllin the amount of air to the engine physically, does it really make a difference to have an intake?
jus a thought, correct me if im wrong, cus id like to know

but buddy, if unotice ur car performs better, than sweet, hehe, its all u can ask for rite

 

You cant honestly say it impacted your mpg either. I mean there are too many uncontrolled variables to determine that true. So that satement is irrelevant.