It appears that there's a crack in the exhaust manifold on my wife's 190-E 2.3.
Is this a problem?
Can it cause problems?
Can it be fixed (e.g. welded)?
Is this a tough job to replace (doesn't look like it)?

Thanks in advance (TIA) for the help / encouragement.

Almost all of them crack at some point in their life. I have replaced no less than 50 or so. I have warmed them slowly and braised them a few times, but I don't know the long term worthyness of this.

I would just replace it so exhaust doen't enter the cabin.