Only problem is none of the Panther II designs were ever issued and none saw combat. The Chassis were captured at the factory overrun by US forces and the special "Schmalturm" was being manufactured near Kassel and the facility was captured by the British.
The turret and chassis were never married up other than a couple non operational prototypes. The only existing turret was inadvertantly dragged down range at Bovington. It was too far damaged to be refurbished and now sits as a remote display. Fort Knox has a Panther II chassis but the turret is from a Panther A (Re; curator Charley Lemons). It would have been a mean tank, with armor beefed up 25mm interrior and carrying the King Tiger's 88 with a range finder. [:@] Don't know if any upgrade was made to the Panther's Maybach engine, but that's a lot of added weight on an already strained engine.