I have JBA headers on my 03 4x4 4.0L and they fit - barely. The clearance between the oil filter adapter and the PS header is very tight. Some people have reported serious interference there but mine weren't that bad. I ground a small bevel on the collector flange to increase the clearance.
Be forewarned - these are quality headers but they are rather expensive and require 1~2 days to install them. If you want performance, a tuner from BamaChips will get you more for less money and a lot less hassle. If you want sound, a performance muffler will give you much more than these headers.