In the upper right hand corner is an example of a class 4 faust. These were mainly the supplementary capital ships and enforcer units of the Sturmtiger's army. They were massive in size and power though these faust usually gave up versatility and movable limbs to achieve this.
The rest are class 2 faust, you'll notice that some of these class 2 can carry class 1 to act as their own faust. A very common arrangement which worked out pretty well in practice. Not much else to say other then they were more powerful then class 1 faust.