Some 20+ years ago, I inherited my SL from my grandfather. I quite literally grew up in the passenger seat of the car, and when he passed, the family turned it over to me. The car had been sitting idle for 10 years at that time.
Upon hearing this, my mechanic (Steve Marx in Costa Mesa, CA) gave me sound advice: you don't want to restore this car. This is an heirloom, not a show car. You want a show car? Buy one that somebody else already restored, who won their trophies, and is ready to move on to a new project.
Since then, other than mechanicals, I have rebuilt the seats, had the interior wood restored, replaced the heater levers (pure torture), wet-sanded and polished the paint, and addressed a variety of other little cosmetic items. But I am not afraid to drive it. Were I $100k+ into a full restoration, I would be paranoid to drive it. But that's just me.
My dilemma is I really don’t want a car I’m afraid to enjoy/drive. And this is an area where I’d appreciate the advice of others.