are all headers pretty much the same or do you just try to find the best price, or are there diff kinds of metals and if so what type is the best?

 

Definately not all the same. DC Sports, Megan Racing are good companies.

 

do diffrent headers effect performance? if so what are the best 1s?

 

yeah different headers most definately effect performance, the BEST one, Mugen or JIC but unless you are building a 9sec dragsters that will never see the road don't waste your money.

 

WHY NOT???????????????????

 

Because the difference from a Mugen or JIC header compared to DC, Greddy, or Megan will be maybe 1hp if even that. If your all motor civic is putting out 350+hp, then yes go for a JDM one, but otherwise it is just a waste of many hundreds of dollars.

Also, 4-1 headers are generally used for track use, and develop more high-rpm power, while 4-2-1 are used more for the street and make tq and hp.