The frames need thorough cleaning but not all rust damage can be seen on the outside. Use plenty of rustproofing on the frames and make sure all sections are treated inside and out. The car is NOT waterproof. Rear wings are notorious, especially on the 8. Galavanising could be a solution.
Plastic replacements are available.
Nose panel traps mud along with inner wings and all corners will start to rust. Clean the whole floor sections. Rust is invisible beneath the white sound deadening coating. There are still plenty of new panels to be found. General Hydraulics Don't mix up the fluids.