headers or not to headers

I have seen headers as well as manifolds leak/burn gaskets. On my friend's 71 challenger 440, which I babysit, the original magnum manifolds make it difficult to access spark plugs and they constantly burn pipe and flange gaskets. I am begging him to pop for the tti headers for his application. On my 66 Dart with a 360, Doug's headers have been great with minor problems fitting them and so far no leaks. You can have problems with both and on some cars like early a bodies, manifolds are hard to find.