Yes, Mr. Penguin is correct. He was the wise, experienced gentleman who helped guide me on pumper carb selection once I decided to do it since he's run all 3 carbs. I haven't done the Stroker header but it's in the near future, along with their shift kit and ilder gear fixes. Recall I was cool with the power level but wanted to wake the bike up. I think the Stroker header will add a little of both since the stocker was a carry-over from the 250 and is smaller than the exhuast port!
BTW, pumper carb or not, all KLX owners should install the Ty Davis hot start valve! It is so convenient and works so well it's the best $70 I've spent on my KLX. You can even use it to lean the bike out a little if weather/riding conditions warrant it and it is so convenient being right there on the clutch perch. With this I don't see any reason to go to a manual decompression release (BTW, Honda says the same thing on their CRF450 since a hot start is stock along with the autodecompression, which KLXs already have).