Hi Josh -

Both your W111 and W115 posts leave me confused. You say (in 115 thread) that you are not interested in perceived market value, which I interpret to mean that you don't care if you are upside-down on the cars, you want to fix and keep them even if it is not cost effective. Is that correct?

If so, what is your goal for the car(s)? To keep and drive for 40 years? To be entombed in one of them (if so, which one)? To have show cars? In one place you mention not having a lot of money and elsewhere you ask about costs for a rotisserie restoration.

As to specifics, I can't really address the bubbling rust on the fenders as I've never dealt with that. For front fenders it's easier to replace them. Not sure about rear quarter panels.

Do you care if panels don't match perfectly?

For surface rust inside trunk I would definitely treat rather than replace. What is the point of replacing it unless you are going for show-car, which I think you are not.

Probably the more relevant issue in the trunk is stopping the future water from getting in. In both cars the issue is either the trunk seal or the rear windshield seal. The rubber mat in the trunk of many MB cars makes it worse by trapping the water so it can't evaporate.

All of the choices depend on your budget and your goals, neither of which are clear.

cheers
Scott