OBX Headers 1992-2002: Should fit all years of the 3.9 so long as the mounting flange is correct. It seems that the only reason that it doesn't "fit" the earlier models is due to the EGR system.
JBA Headers at Summit.
JBA Headers at JEGS.
These pair of headers may or not make it for...
I didn't find a post completely devoted to this upgrade so I figured I'd start it off. I think I found the greatest upgrade for the 4.7L (with help from HemiDak on Dakota-durango.com), the 2002 Jeep GC TCM swap.
Personally, I Haven't been able to try it out but I have done enough reads on it...