Mustang Noobie

Hello i just recently joined and i just bought my first Mustang. Its a 2002 3.8 V6 and already has dual exhaust. I dont know what kind but i would like to find out, is there any way for me to find out? Also i would like to know what are some quick HP gains that i can get. I am no mechanic and like i said this is my first stang and i love it.