i would go with a 2005 or newer Hemi. What trans do you have and are you 2wd or 4wd? Get the engine harness and PCM as a minimum. If you can get the engine bay harness and DBW pedal that would be a good idea.
What was your search criteria to come up with that? I found the $45 exhaust manifold searching for a 2007 JGC exhaust manifold 6.1 and the description was listed as 1959 Pontiac.I've read that Jeep Grand Cherokee SRT8 exhaust manifolds fit the Dak/Dur frame, and are basically headers. $90/set on www.car-part.com
Are you talking about headers for a Hemi in your Durango vs. in a Hemi in a Dakota swap???so no headers, good headers would fit? otherwise maybe ill make my own