Hi. Not sure how much I can add here, but I've rebuilt two cars that were written off as "total loss". Neither was a Mercedes, but the basic issues are the same. I "saved" these cars because they were both valuable and rare. I restore unusual cars as my hobby.
Also, I own a similar car to this... a '96 S500 Coupe... so, lots of the pieces are the same as the eBay car.
My 2 cents are that I wouldn't consider this project unless you have a "donor car" to take parts from, lots of tiime, and adequate, protected space to work. It WILL take longer and cost MORE than you think. Did I mention lots of time? Somehow, it always works out that way. In the restoration hobby, an old, beat up, rusted out car is always worth more than one that is "incomplete" or in pieces. Ads are plentiful of failed projects... hence the name "basket case".
Despite how well you plan it out, you won't know what needs to be replaced/done until you're well into the project. There WILL be hidden damage. Also, although the "big" parts are expensive, my experience is that its all the little clips, connectors, tubes, etc that will eat your time and money. Unless you have a donor, this small stuff will drive you nuts. You can "jury rig" lots of this stuff, but on this quality of car, I think that would be foolish.
I've been into the cowling area of my Coupe, and I can tell you that there are lots of these little items there. Many are plastic and you can be assured that they are gone from the fire.
Also, with fire damage, you need to worry about much more than paint. Sheet metal warps pretty quickly with localized heat. I'd be surprised if the hood on this car can be restored to its pre-fire condition for any reasonable amount of money... especially in black. Black paint shows all flaws... I'm reminded every time I shoot black enamel on a freshly worked body part... and then get to sand it off and do it again.
And, oh, did I mention that none of the sheet metal on an S Coupe of this vintage will interchange with that of the more plentiful sedans? None. Zip. Zero.
Is there any good news? Well, yes. While looking for a headlight for my Coupe, I found an S600 Coupe in a salvage yard down South... think it was in Florida. So, there are donors around... but, not many.
Hope this wasn't too discouraging... but wanted to pitch in my views before you leap in with both feet....
KenP
PS If one of you does dive in, I'll be happy to lend whatever advice/help I can. I'm only an hour from Richmond myself.