United States
At that point, its an SU-76. Trading a 4th hit of hp for 10 less range. Damage would need to drop a bit too.
As is, StuGs are a good way to support a panther against IS2s and Pershings, however. Do you really want to trade that off by lowering its pen?
It would still be distinct enough, I think with target weakpoint superior pen to P4 and its low cost it would be an acceptable support for the panther against everything but the super heavies.
Edit: Pardon I didnt fully answer your question. To be honest I find generally ostheer infantry based AT to be better at supporting a panther against the pershing and IS2 not stugs atm. Stugs are ok but lack the range to properly zone an IS2 or pershing particularly once the former hits vet 2. You are better off upgrading a squad of pgrens, getting an extra pak or saving for a second panther than using a stug.
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