Seems like you're really restricting the choices on yourself.
You don't really say why/what needs repairing. Most important is the overall condition of the body. If it isn't rusted out at all and the interior is fairly decent, you could fix what needs repairing and have some fun with it. If that's what you're into, that's another thing, are you interested in old cars in general and Mercedes in particular?
If it is worth repairing is up to you, people go to great extremes to repair vehicles that aren't nearly worth the cost and effort.
If the car is in generally good shape, you may be wiser to just sell it as-is rather than parting it out.
If you think you can fix it up AND MAKE MONEY ON IT then for Cripes sake SELL SELL SELL it!!!!! You DON'T want to go there. Here's the tip of the year for ya: It DON'T work that way!!!!!