Just getting some ideas
 

I'm looking at buy a 2001 honda civic and wanted to add a cold air intake throttle body and headers but I am new to Hondas so I was wonder what company's are trust worthy and worth the price?

none of those mods will gain you any real hp on a 2001 civic so none are cost effective. but if you insist on it then use DC header and AEM intake.

Ok we'll what would you suggest then?

You can use AEM, aFe, K&N or Injen type of cold air intakes and a good quality header.

i would suggests spending your money elsewhere. i own a 04 which is the same thing the only mods i would spend money on performance wise is suspension. the car mite be slow but you can make them ride on rails with the rite upgrades. look into coilovers.sway bars,tie bars,energy suspension bushings.