Hey Pauly, I think he meant de-rusting (I hope!!)
As with mods, the way I see it, as with my car, all the mods that I have done, everything can be put back to stock. I wouldn't do anything that couldn't be reversed if it had to be done. For example an RB engine conversion. If I was to fit a turbo RB and use the transmission from one, you would have to remove the original transmission mounts to fit the bigger turbo box. I haven't touched mine (used a NA RB box which is smaller) and as I am going back to an L series motor, everything should go back as it was from Nissan. If you decide on fitting a L28 or Cummins diesel, as long as you keep all the original components, you should be fine.
If you want to change the radio, find another average console and butcher that; same with the interior, remove what you want to keep and buy second hand stuff you can modify. Then if you ever want it stock, just remove and replace. Just my 2c!