Hello. New guy here. I have the opportunity to acquire an 89 Mustang LX 5.0 Convertible that has been owned by various family members for the last 25+ years. The car is basically all stock and in good condition with around 120k miles. There isn't any visible rust on the exterior, or the shock towers, but there is some surface rust underneath the car. The floor pans look ok. The car hasn't seen winter for the last 15 years, but it was driven through a few winters around 20 years ago. My question is: will the surface rust that is present now continue to get worse and worse and eventually cause structural issues, or is this not a big concern? Is there anything I can do now to minimize the rust damage from spreading? Here are a few pics underneath the rear of the car: