Headers vs Hi-op manifolds

So for my 400 HP 340 which would be better Doug's headers or 340 hi-op manifolds? Would I lose a lot if I went with the manifolds and has anybody had their manifolds coated like the headers come? Also am I going to have problems with either inconjunction with my eddy head? Thanks in advance (if you wanna see the specs to my 340 build it's http://www.forabodiesonly.com/mopar/showthread.php?t=153956