Can you? Really? Your body and bumpers are the same height, and you can climb the same size ledges?
It's certainly possible that where you wheel you can get away with 37's no problem, and if that's the case you can probably get away with smaller axles. But the only thing that's "the same" between properly setup tons and 40's or 42's and smaller axles with 37's would be the clearance to the bottom of the diff.
Like I said, that may be perfectly appropriate--maybe even better--but it certainly not "the same" in any sense of the word. I can get "the same" clearance on an S35 and 35's probably, but that's not the same either.