How good is the stock head pipe on a 400?

How well does the stock head pipe work with mods like wb exhaust, wb rev limiter, and a K&N w/ outerwear- no lid?
Would it be best for me to leave the stock head pipe on or replace it with an aftermarket one?

your stock head pipe will work just fine, but an aftermarket headpipe would give you more power.

I read somewhere that the head pipe on the 400EX is of great design. As a matter of fact, they said that unless you are running a big bore kit you should not replace it. They said that the loss of back pressure would actually hurt performance. So unless you are going to put a 440 kit in it anytime soon, I would advise against the new head pipe.

[WB400ex]

i heard that the stock head pipe flows good and that unless you are racing you really dont need an aftermarket header. they said its not worth the extra 200 dollars for the header

[knighttime]

It depends, if you want awesome thottle reponse and more power and have $200, the header is cool.

Yeah what he said.....:blah :blah :blah