This message from Bill Schooler:
My guess is a 300SL. Just looks too 'brawny' for the 190 model. Couldn't begin to come up with a year. Nor does it appear to be the gull-wing version, but with that cover on one can't be certain.

It looks like a 1957 MB 300 SL Gullwing (or a kit? Those pipes don't look like MB stuff). If real, this could be a $300,000 car. Seems wierd that the pipes stick out the side, the bumpers are missing, and the grill isn't in tact. Or it could be a VERY EXPENSIVE factory race car?? - Larry

From Robert Alan Reisse:
It certainly looks like a MB 300 SL Roadster that has been slightly modified for racing.

I think that the 300 SL Roadster was only manufactured in the period from 1956 to 1958, but my memory may be faulty on that. I think the most telling feature are the vents on the front fender. I have only seen them on 300 SL's. - Bob Reisse

From Max Heim:
Definitely a 300SL roadster, 1954-63. The lack of front bumper, and the side exhaust, suggest a 300SLR (racing version) -- if so it would have a rear deck fairing with headrest bumps (can't be seen under the cover). 300SLRs are pretty rare and mighty expensive, so it may be a replica.

From Hans Duinhoven
Great pictures - Merc absolutely is a 300 SL - special version - priceless cars these are... 300's were recognizable from the inlets behind the front wheels. 190's did not have these...

From Michael Singleton
It is definately a 300 SL. the SLR model was significantly different, note the pictures at the following site: http://www.efini.net/otherautos.htm, note the substantially different body, markedly different frontal aspects and profile, along with the air intake on the hood (bonnet) etc.

From Michael Singleton
After a little more checking around, I found the following:
http://www.scottgrundfor.com/projects/300slprototype.html, this car has an answer for the side exiting exhaust pipes, that I do not believe were fitted to the production 300SL's.
How's that?