I've used the HL Panzer drivers viewing slit (slightly repositioned to the outside) and added the frontal bolt on armour from 2.5mm styrene sheet. The nuts are M2 with a short piece of M2 thread. I had to buy a metre length of threaded rod, so I guess I've got enough M2 to last....

The lift loops on the top body are made from copper wire (available in any convenient wall in your house). No seriously, it's an extremely easy material to work with if it's annealed. (To anneal copper heat it up to dull red with a butane torch and quench in water. Do it somewhere that's fireproof). It will work harden with bending or hammering, so if it gets difficult to work with - anneal it again. The loops were bent around a piece of rod and then the ends were hammered flat and trimmed off with a file. I've used Milliput to simulate the welds to the body.

The driver's pistol port was made from a bit of scrap that came out of a cd drive (or something). I routinely strip down my old computer components looking for motors, interesting parts, small screws etc.

I decided to make the StuG fairly late in the production run so I've simulated the interleaved plate welding on the back of the body.