Bertone has done little to no designs for Fiat, but have spun concepts off of their cars, like the Panda in 2007.
Bertone has not flourished to the extent that Pininfarina has. After Nuccio's death his wife and children have controlling interest and the company hasn't had a positive direction. Still one of the most distinguished and respected auto design firms in the world. The halcyon days of Gandini are long gone, however.
Pininfarina is basically THE car designer, but not the coachbuilder, for Ferrari since basically the 60's. Bertone designed the 308 GT4, a wedge design, and a four seater, that was replaced much later with the Mondial. It was immediately succeeded by the 308 GTB, but Pininfarina, and a two seater, so it was the same engine but a completely different. Ferraris are actually built in the Scaglietti works inside Ferrari, which at one point was a separate company and a coachbuilder, they built almost all the Ferraris, and even hand hammered the panels on the flagships models like the 512 BBi BY HAND, so the car was completely hand built....which stopped in 1984.
Ferrucio Lamborghini was a very successful and wealthy industrialists in the tractor and air conditioning industries. He owned several Ferraris, notably a 250 GT
and was apparently a heavy clutcher. Lamborghini was a
mechanical genius in his own right, not just a businessman. His tractor factories had far superior machining and production facilities than Ferrari.
He took his Ferrari's clutch apart and discovered it to be the same clutch that he put on some of his tractors. He
went to Modena and approached Ferrari, and he actually did
have a conversation with him, though Ferrari had no regard
or patience with Lamborghini...telling him..."Lamborghini...you may know how to build tractors but you do not know how to handle a Ferrari," then abruptly left.
The Lamborghini 350GT was the first effort and was as fast and well made as anything Ferrari had. Then the Miura came along and Ferrari was forced to look seriously at the mid-engine sports car market. Ferrari's stubbornness cost him in the marketplace. I think it's hilarious that when he actually did get full swing into the mid-engined thing, that is, after the 308's were popular, he went to the 365 and 512 Boxers.....which had FLAT TWELVE engines, that is, and many don't get this, horizontally opposed twelve cylinder engines, not V twelves. The cylinders going back and forth looked like boxers boxing so they called them boxers. There will probably never, ever be a flat twelve engine produced in the world. Oops...I'm rambling, sorry.