I've seen several shops with that very "slogan." But, what does it mean?
Nothing.
It doesn't mean a thing. Aside from cars and trucks made in Asia, Europe and America, what are there. I suppose there could be some cars made in Africa (ok, I just checked, and aside from cars that are also manufactured in other countries {Toyotas for example} there are VERY few made there... but Superformance is a VERY cool company) but not in a high enough quantity to be of issue here in Atlanta. There isn't anything happening in Antarctica... or Greenland... and not many Australian cars come here. 
Back to the point.
They are saying that they specialize in EVERYTHING. If one specializes in everything, they really mean that they specialize in nothing. I mean, really. How can you specialize in everything?
Now, let's tie this back to real estate.
Have you ever seen an ad that said "I specialize in Buyers and Sellers"? I guess that means that they will deal with anyone but lookers... But, isn't that what everyone else does? Are you truly a specialist if you think you do EVERYTHING? The short answer is NO. the long answer is No, you are a generalist.
Why not just say that you generalize in everything?
Maybe we should try a little truth in advertising. Sam's Club here in GA had to change their name. They had called it Sam's Wholesale Club, but they sold to the public (that would be the definition of retail, BTW). Even though they argued that they only sold to members, it was determined that since they were selling primarily and by a wide margin to non-resellers, they were a retail outlet, and not a wholesaler.
I think that people who "specialize in everything" should be held to the same standard.
Nice car. Love it.