Two problems related to body have been reported for the 1999 BMW 323. The most recently reported issues are listed below.
My 1999 323i caught fire immedietly after turning off the ignition switch once parked. There was a loud "snap", followed by large flames coming from around the hood and front wheel wells. The police and fire department arrived within 5-7 minutes (fortunately they are both located less than 1 mile away). Once the fire was put out, my car's front 1/2 was melted into my parking space. It was a complete loss and I am expecting that my auto insurance will pay very little; regardless that the car was in very good condition prior to this incident.
The subframe has ripped away from the floorpan. Through investigation this has been determined to be a very common failure on e46 BMW 3 series. This should be a mandatory recall by BMW to fix this issue. The subframe should last the life of any car.