Cheers Huib,
Yes, I always create completely new units instead of changing existing ones.
I am now testing the gradually improved units with AF on and AF off.
Testing so far would support the idea of upgrading the StuGs up til 1500 meters (6 hexes) with identical hard values compared to Pz IV H.
They'd still not be supernatural, but at least they could then fire one volley vs IS-2s and T-34s expecting to achieve something.
The new armoured leaders help too. I opted to have a lvl 4 battalion commander and lvl 3 company commanders, giving each StuG pack (Coy) a leader to improve things as well.
Did you see Mike's bitmaps from the other thread:
Über kool, I would say