So, looking through the World War Wednesday videos, I saw that you can research specialist versions of tanks for various purposes. How exactly do these work? Do we attach regiments of SPAA/SPART guns to divisions, or do we have to include them as support companies? For that matter, do we have access to regular artillery and anti tank guns outside of support companies? Finally, can we convert old equipment over to specialized versions (Panzer 3 to STUG 3 for example), or do we need to build all of it from scratch?