there are tons of things you can do. but first decide and plan out what you want for your car. don't just randomly go and buy an intake header, exhaust etc.... give yourself a budget. if you want the most hp for the least amount of $, nitrous oxide is the best way to go. there are 4 routes you can go.
NA
nitrous oxide
turbo/supercahrger
SWAP
or combination of the 4 I.E. nitrous w/turbo, or turbo w/swap etc...
the reason for this is simple. if you get performance parts like intake and headers with out planning ahead and later decide to get an engine swap, you will know that the intake and the header won't fit the new engine. same goes with turbocharger.
one thing good about nitrous is htat you can add it later even if you have intake, headers and other bolt ons. with a $1000, you can get the ever so popular i/h/e (intake headers exhaust.) later if you want more power you can add nitrous. but as fairlady said, if you are going to change to a turbo or an engine swap know that those bolt ons will be no longer needed. anyways, if you didn't get your car lowered... go do that. lowering is probably the most basic, its cheap and makes the car look hella better.
for springs you can get an eibach prokit (1.5" drop)which cost about $190. shouldn't pay mroe than 200 for that. installation should cost no more than $60.
if you want the basic i/h/e for a honda consider the following:
AEM Cold air intake: no more than $190..install:$40
DC 4-2-1 ceramic headers: $280 install $50
GReddy evo:$450 install $40
well this is only a suggestion.. and always remember get BRAND NAME!!! those company worked hard to get that kinda reputation.
remember that $ is the MAJOR controlling factor. so what is your budget? then we will talk. hope this helps