What's the point of beating some guys at something they don't practice but you do? I could see why you would want to do more kipping pullups than they do without having trained for it, because that would make you an awesome puller-upper. I can see why they would want to deadlift more than you do, by the same logic. But why would you want to beat them at a game they don't practice?
There's this guy who keeps challenging me to grapple with him, so i do - i do BJJ and he doesn't, so i see why he would want to beat me at it. And after we're finished he always says "We should do some stand-up sparring" and i'm baffled he says that. I don't do any stand-up training at all right now and he has a brown belt in kyokushin, so why would he want to beat me at it?
(the obvious question here is "why do i grapple with him", and the answer is that i do because he outweighs me and is far stronger than I so i still see a point to it)
Also, i think the answer to your question is obvious - if you want to show them that you are stronger than them, do squats and deadlifts and bench.