I just bought an 83 280 zx to restore. so hopefully you guys can help me with several questions regarding the chassis. I just stripped the carpet and seats out and the floorboards are pretty rusty in a couple places so i am gonna fix that up. I have heard rumors that these cars can "break in half" if the frame rails are rusty. I think mine might be i cant quite get up under and see at the moment. If they are, is it safe to jack the car up? how much of the rigidity of the car is from the frame rails? Is there any sense in stiffening the frame up more than stock like on my 5.0 mustang i put subframe connectors? or am i just paranoid? thanks for any help.

p.s it is N/A 5 Speed and probably wont ever see high horsepower levels.