is it wrong to take a apart a perfect srt for its drivetrain?

What CudaSRT said.

Assuming you use the engine and trans out of the Magnum, and perhaps the front seats, the question becomes how much is the shell worth. Unless your willing to sit on a tore apart car for at least a year, I doubt there's 5K there. Could be wrong, but I'd sharpen my pencil before I went that route.

Regards,

Joe Dokes