correct use of displacement and normal maps in blender


I prepared a model in zBrush, created normal and displacement maps and of course
the uv’s.
Then i did a render in c4d 11.5. It looked ok, but the shadows didn’t render very well and there were some artefacts due to the normal map.
So i gave it a try in blender 2.63.
Here i have some troubles retaining the details. There are several values for displacement that interact. Is there a way to calculate these values properly?
Can this level of detail be rendered at all in blender?
I understood that blender needs a subdivision surface modifier in order to displace
the geometry. But when i raise the value to 5, the program crashes.
What are the limits for subdividing the mesh?
The two renders are attached.

Thanks a lot for your interest.