Re: Prefabs and Entities
Sure, only custom materials, props, VCDs, etc. would need to be BSPZip'd, or Pakrat'd into the bsp, your entities and brushwork will be compiled by the first of three compiler functions, bsp.
1) BSP...The tree
2) VIS...What can be seen and from where, visibility, leafs and portals.
3) RAD...Radiosity, the static side of lighting and where it will burn and on what.