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

Figure out what type of resto mod you want to build and just get those parts only to build it. By parting out your Magnum, you create TWO projects. You'll be forever dismantling the Magnum for parts to use and parts to sell. All the time you spend taking it apart and selling off the parts is time you can spend on the Dart. Plus the issue of space, it isn't worth it. An SRT Magnum is very desireable. Sell it for the most you can and then get going on the Dart...