Can't vouch for this particular seller, but you can do some research on the tire and brand at:

http://www.coopertire.com/tire/

I have used Cooper Cobra G/T and Cooper Classic II with good results.

Can't find the specific tire you are talking about under any of the Cooper brand names, however, they make tires for other people. For example, some of the Sears Guardsman tires are made by Cooper.

I found a reference to your tire on the USA DOT Web site:
http://www.nhtsa.dot.gov/cars/testing/UTQG/table_4.htm#Brand:%20EL%20DORADO

Then I found this web site for the brand of ElDorado tires:
http://www.eldoradotire.com/

If you click on the "Company Profile" link, they discuss who supplies their tires now - Cooper Tire.

The Eldorado Legend specs are at:
http://www.eldoradotire.com/prodinf.asp?name=legend

Personally, I would be a little nervous putting these on the big body W126 Mercedes cars like the 300SD. But I would put the tire on my lighter 300D car. Most tire shops would not put this tire on any Mercedes - they always want to sell you a higher-rated tire. Usually they want to sell an H-rated tire with a higher load rating - stiffer sidewalls.

I assume he is selling you four tires, shipped, for $151? Sears routinely sells their cheapest tires for $100 for a set of four.

Ken300D