All Mariahs are "Equipped like No Other Boat in the World". So in a nutshell, any Mariah you look at will have many nicer features than other boats.
Diablo is Mariah's entry level boat. Still light years away from most entry level boats.
Barchetta was a model name used in the early 90's. Replaced by Talari.
Talari & Shabahs were the most common model names in the later 90's up to the end, in 2001. They were both similarly equipped.
Take a look at
This Thread paying attention to posts # 5 & 7. This might help clear it up, or maybe just confuse you more.
One thing I do know, the "Z Series" boats were the best equipped ones of the line, came with all the options, and include special fabrics, color combinations, accessories, and decal packages. So if you're in the market for the really nice ones, look for a Z in the model number. ie Z212, Z250, Z302, etc.