Well, the fact that Guards into M3 beat an Armored Car in a straight fight is false, at least in live (where 20mm cannon does 25 damage unlike how it is in the beta). The 20mm cannon + the normal MG would kill the M3 before Guards are able to shoot the second time. The only chance to destroy the AC is if your opponent microes badly (like retreating the AC and then getting chased, since PTRS have longer range than the AC).
Su-85 can drive backwards faster than Pgrens can run forwards so I'm not really sure where the problem is... you just drive backwards in a straight line and they'll never hit you.
Also: mines, snipers, flame engis, molotovs, PPSh, guard grenades, shock troops and plenty of other things all completely shut down Pgrens with schrecks.
I think he means when Germans use the sprint ability on infantry