W108 or W115

Hello and good day, after my friend told me a few days ago that he used his old Volvo 140 next to a Borgward Isabella Kombi every day, I had the stupid idea to get another oldtimer (next to my current bus). I would like to drive it regularly in the season, preferably daily. Besides a W115 I also found a W108 with nearly the same basic data and condition which both agree to me. Unfortunately I have with both models so far No experience. I had a W123 a few years ago. Is my project at all possible to use the Mercedes as a “daily driver” without excessive service/care and restoration effort in the fine weather season? I don’t want to start a “bar without ground” project and did not want a “water-soluble” car that has to be overhauled after a few summer thunderstorms. What would you take, with which motorization? Is the W108 more rust-prone and more sensitive than the W115? another model more recommended? Thank you. Markus