Even though "Grotti" is the plural of "grotto" in Italian, it is presumably a play on the English word "grotty," meaning "seedy." Grotti's logo caricatures Ferrari's; in GTA San Andreas, the galloping horse is replaced with a rabbit/hare and, in GTA IV, instead of a galloping horse, the logo depicts a horse sitting down.
The Grotti Showroom in Liberty City is one of the many buildings that allows you to get to six stars wanted level quickly. Just get to the first floor and start shooting. You can even hold the people inside the building hostage by blocking the front door with a car.
The company name could be a nod to John Gotti, a Mafia boss of the Gambino Crime Family.
If you enter the Grotti Dealership in Middle Park East and use a Baseball Bat to knock out all the windows on the main floor, the windows on the second floor will begin to fall either on their own or if the player walks into them.
The doors in the Algonquin showroom will occasionally lock but the windows still manage to break.
It is shown to be a very prominent car manufactuer, as shown when companies like ElitasTravel.com call themselves the "Grotti of air travel," similar to how some companies call themselves the "Ferarri of" their work.