Will BBK shorty headers or JBA shorty headers really add mush of anything to my 2002 v6 mustang?

I have a 2002 mustang v6 with custom stereo and Steeda dual cat-back exhaust kit from american muscle.com I wanted to get some bbk or jbl shorty headers. Will those really add any hp or performance or are headers for more advanced cars. How much does install usually cost for headers. I am planning to add BBK CAI and a bbk throttle boddy. Plus the headers. Does this sound like a good plan, and will it all work without any other mods.