I bought a 1974 2002 from a friend who restored the car in the 1990s. It has had previous rust repair in many areas (driver's front subframe rail, driver's floor, rear shock towers to name a few.) It was painted a very dark green (Nissan color) in the 1990s and clear coated. The exterior has had all trim removed prior to painting and looks pretty nice. I bought the car a year and a half ago and have done a few basic things to it. I removed a roll bar and 5-pt belts (it has seen some track time at Summit Point.) I installed retractable seat belts from Blue Devils, an S14 starter, a nice set of E21 Recaros, plugs, wires, rotor, cap, fluids, repainted E21 turbine wheels with Toyo tires. It drives well. I noticed some rust bubbling from the metal floor plugs underneath the car, so I finally pulled out the carpet. I found a repaired driver's floor section and intact-looking black tar sound deadening in the rear and passenger side. I used dry ice (thanks Dry Ice Ice Baby article!) and discovered that all the metal plugs have rusted through (most fell out leaving holes.) One of holes is perilously close to a rear suspension mounting point. The floor is intact where it meets the inner rocker panels save for a 6" section along the rear driver's side, where it has rusted through. The outer rockers appear sound. I'd like to have these rust holes repaired/patched. I don't know if I should buy a new floor section for the driver's side rear where the damage is worst.
So I bought a rear driver side floor panel. I dug a little deeper. I found the inner inside fenders (which were covered with sound deadening) have rusted through as well. I also removed the cardboard-like stuff on the passenger firewall and found another hole in the floor there. The inner rear fenders (next to the springs) appear to have been repaired in some manner. And I've added a picture of the previous driver's frame rail repair, which now has surface rust.