In need of heavy advice(i'm an idiot)

Hey guys, i'm new, and i dont know jack about cars. This poses as a problem, as i see some sweet lookin civics on the road and on the net. I have a 2002 civic ex coupe. I want to get some rear altezzas, some special air intake(dont know anything about this), and perhaps a new exhaust system. One, will this void my warranty? Two, any advice on these things? As i said before, i'm not good w/ cars, so would it be best to leave it in the hands of a local car joint? thanks guys.