I did this recently. I followed the chilton/hayes procedure and first removed the downpipe from the manifold and then removed the manifold from the head in the car. It is moderately difficult but overall worked well. I doubt the manifold would come off the head vary easily without removing the down pipe first. As to leaving the manifold on the head and removing the complete assembly it may be possibly but would be very heavy.

Is this a turbo or NA?

I've never done this before, but I think if it were me, I'd try to unbolt the manifold from the exhaust and take the head out with the manifold connected to it.
For a turbo car that would mean unbolting the mainfold from the turbo, leaving the exhaust including the turbo all the way back still in the car.
For a NA I guess that would mean unbolting the manifold from the flange on the cat pipe, leaving the exhaust including the cat pipe all the way back still in the car.

It seems to me like that would be easiest.

That way you get to deal with the manifold bolts 'on the bench' so to speak rather than with the cramped space while it's still on the car.

I would definitely recommend new manifold studs and nuts and gaskets for this job as well.

If you can't use new stuff, you'll have to clean it up as best you can I guess... Try to clean ALL the rust off of the studs and nuts. One of those evap-o-rust products might work well for this.

Use LOTS of antiseize when you put this back together, whether you have new parts or not.