of course the wreck of a completely destroyed tank has less weight then the usual vehicle. I mean, for example I doubt this Panzer IV here to have somewhat the same weight as before
. Obviously ... also poor bastards >.<
On the other side, a Tank raming another tank should not leave much of an impression though. The worst thing eventually which should happen is disabling the engine as they usualy dont take the force that well. With the Panther (early models) it would have a high danger to start a fire ! 70% if not more of the first Panthers which saw action in Kursk 1943 have not even seen an combat cause of engine issues and some burned out completely beyond repair ! This got only later fixed with the G model beeing the most reliable Panther of course. But once in a while very brave or might I say crazy soviet tankers would engange in raming a axis tank but even then it was always a rather desperate tactic. One has to remember that not only the enemy vehicle will feel the force of the impact but also the own vehicle ... so this was most of the time done eventually if all the amunition has been wasted or you had no chance to penetrate the target. There have been a few situations where they succesfully damaged the enemy tanks that way. But most of the time they would simply imobilize them.