I bolted the DS header on before I dropped it in. At the same time, I was able to get it out while the motor was bolted in, without moving it. I haven't tried to put it back on though so maybe it is a one way only deal. It was really tight past the bellhousing too.
Not sure it helps, but I went out from the bottom.
My gut says that when I get to the point of putting it all together for real, if I put the motor in from the bottom, it will be with the DS header and steering box all bolted up and missing the PS valve cover to get enough room to get it up into the engine bay. PS header was cake with the motor in, and I don't see it making any difference clearance wise anyways.