getting started...

okay, i have some questions that i want to find out for my car. those idiots on importmix banned my ip address for calling a honda-basher "hamster penis" and "anal wart". anyways, on to the questions...

i have a 2002 civic dx, and yes it's all manual...manual locks, mirrors, seats, windows, ect. and it only has 115 hp(i'm sure you already know) stock but i think that's pretty respectable for the size of the car and engine. i didn't have enough money to get me a "higher-class" honda, so i'm stuck with this for a while(but i don't regret it).

to increase hp, what should i work on first?
a. intake
b. header
c. exhaust

and what are some of the top brands of each one of those? injen? dc?