I know it seems unfair, but I hope it's not.
These cars are all over the web. If you google "Alfa Romeo Barchetta", you can find 25/30 of them. To find how they are named it's not hard, after all. If I do not have anything more, that would be enough. But when I do know the builder, that's what I'm looking for. Those names are pure fiction.
Well OK, but 15 ARB took a lot of finding..
Google even for the answer, "Alfa Romeo 1900SS Barchetta Stradale 1954" and you don't get anything without a great deal of patience and certainly Googling for Alfa Barchettas doesn't bring it up at all. It took me many hours to get that name and there's no mention of the builder that I have found on the web, so it was probably just a guess?
When I started this goup puzzle I knew I was going into many troubles.
I'll try to be as equal as possible.
I had 40 cars and many of them were/are built by the same few names. This is why I decided to award 1 point for 3 correct guesses. You can find a good number of them within few minutes BUT not the correct info. I had to dig a lot for that. I received papers, I made some phone calls and I had to ask to many people in the know.
There still can be errors because, like you wrote, there is a mistery surrounding these cars.
I didn't want to award 11 points for just 2 names: Greppi and Salerno.
On the other hand, how can I award your efforts for finding the model's name? In other cases those names were easy to find and I don't know how to set the limit.
I decided to give points only to complete answers and the builder was missing. I know he just guessed, but he did it many times before he found the right one and in this case it worked. It won't work for the missing ones, but with the right questions it can be done.