what kind of ecu chip are you talking about? the "mod chips" that are sold on ebay? or something more respectable and legitimate like a jet chip?
i have heard that all of the "chips" and whatnot are not really that effective. i mean, some people say that they can definitley feel a power increase, but others say it feels the same as stock. its kind of a shaky mod.
on the other hand, the headers will definitely give you some solid gains and a noicable increase in power. i would rather have them than a chip.