On the SturmTiger: 13 were built. These were put into three units StrumPz Kps 1001, 1002 and 1003. They were used exclusively in the West against the Allies. For the most part the vehicles were lost when the broke down and had to be abandoned.
There was only one occasion where Shermans supporting the 35th Infantry division shot up two of these vehicles in the Rhur pocket from Kp 1002. The only documented case I know of where these vehicles actually inflicted any damage on an opponet was at Pier Holland where Kp 1002 fired 13 rockets into the US lines causing 1 Kia and 3 wounded.
The original idea for the SturmTiger was for a vehicle that would be useful in urban fighting like occured at Stalingrad. The vehicles never saw action in that sort of enviroment and proved totally worthless in any other role. It was another case of wasting 13 tiger I chassis to produce another miniscule run oddity AFV of little or no use.