soo.. are aftermarket head pipes even worth it?

..for an X that is.

i have a powercore 4 slip-on, looking at a header to maybe compliment it but none of them show any huge power gains and cut in on the sound (and i love my loud pipe :P). am i missing something or are these things really just not worth it?

tbh, i've only really looked at the fmf powerbomb and megabomb, so if you have your own recommendations for headers.. bomb's away

Well, my power bomb looks cooler, weighs less, and makes for some minor power gain. How it exactly affects the power curve compared to stock, I dunno, I doubt its very much...but it looks less restrictive.
Far as I'm concerned no negatives to report, aside from spending the cash.

A fuel programmer would be the next step, if not both...then again, you could ride it as is.

Quantitatively, I can't say what difference it actually makes. I do know my bike runs stronger now with the Powerbomb header and powercore4 pipe than it did with just a Q4, and that the power curve was moved around from stock when I tried the megabomb and now finally the powerbomb.

First, if you haven't yet bought a fuel programmer, get that.

When I rode my 2008 WR-250X, I tried the stock head pipe versus an FMF Megabomb head pipe in back-to-back comparison rides separated by about 20 minutes.
This was while using an FMF Q4 muffler.

The Megabomb header gave noticably more low and mid-range power while not effecting the top end, at least not as far as I could tell.
I felt the difference accelerating away from my driveway.
That was a pretty good trick, I thought.

You won't get a huge difference, but it does make a difference, and just as with practically any other modification done to these bikes, the satisfaction with the results basically comes down to the rider's subjectivity with the whole thing.

i'll be getting a fuel programmer within the next month or so.
does anyone know if a delta head pipe will fit on a fmf powercore 4?

I had both FMF headers and the stocker mounted at various point with a Q4.
PB was all about high rpm revving
MB definitely shifts power downwards. I think it was slightly less aggressive at high rpms than the PB. Produces a softer tone as well.
Stocker seems higher pitched in terms of noise.
MB actually works pretty well with the stock muffler (even quiter than stock header+stock muffler).
I really liked the power curve with the mega and Q4 spark insert removed with PCV map....too dang loud though. If noise was no issue, I'd probably go with the powercore and megabomb.

I used to have a full FMF system with the Q4, Powerbomb & PCIII. Seemed to have a bit more over stock but it may have also been the sensation of the louder exhaust. Swapped stock header in for a while & didn't seem to make a difference in power or sound to me. Stock header pipe was actually a little larger I.D than the PB from the head to the clamp. Sold the FMF system & went back to stock because it was a bit more noise than I wanted on longer rides. Programmer seems to make the biggest difference in how the bike runs when combined with bolt ons.