performance parts are best?

i got a 94 GS-R with a magnaflow cat-back and now im looking into geting headers and down pipe, which is better DC or Greddy and do headers make a noticable differance?

I am also getting a AEM CAI V2, any of you all have any experience with it? Also what coil springs do yall recommend, iv been doing some research and found that H&R are one of the best but iv seen many use TOKIKO, just wanted to hear what you all think.

and thanks for helping

i have the AEM V2 on my 97' GSR and i love it. get neuspeed springs, they have really high spring rates...

Ok you want a header and downpipes are for turbo cars.
Now I would go with a Dc Sports 4-1 ceramic coated header. Also Yes the H&R springs are real nice and combined with the Tokico shocks/struts it makes a nice setup.

What if im not going turbo yet will 4-2-1 be better or 4-1?

one more thing, is there a difference between stainless and ceramic?

You should get 4-1 for you;re GSR, since they make HP in the higher RPM range. DC is always a good name when it comes to header systems.
Maybe you meant a test pipe? Those are good, but I dont know about smog legal, if you care that is. Stainless is I guess just a little better looking, and ceramics are actually better because they let less heat back into the engine bay.