Sdkfz 250 was used, it being able to disrupt supply line is a gameplay choice, Luftwaffe dropping supply is (if it really did not happen) ahistorical and should be avoided, Sturmtiger was used and did also destroy some Tanks, Night Vision / Infra Red was used
Black Prince was not used.
How is this so hard to get?
Let me re-phrase that:
How hard is it for, you Wehraboos, to understand the conecept that CoH is not an historical accurate representation of WW2?
Go search for that E-100 turret on the Steam Forums. You might have some luck there