I would say give the PIV a slight increase at mid-long range penetration.
Allied medium tanks have the advantage at short range that combines well with their speed. PIV wants to slug it out at a distance using higher armour and better range penetration.
+1 I agree on this point. This tank can't reliably compete with other tanks, although the ostheer and OKW Pz4 is extremely expensive. I voted for the increase in penetration so it can attack better tanks more reliably.