The Indy was introduced as a four passenger replacement to both the Quattroporte and Mexico. Designed by Vignale, the Indy took several design clues from the very successful Ghibli. Power came from either 4.2, 4.7 or 4.9 liter V8 engines, similar to the Ghibli but utilizing a wet sump. Do to the 2 + 2 nature of the car, quite a few of these cars were imported into the US, many with automatic transmission.
The interior of the Indy is quite plush and attractive. Early and late cars have different instrument facia design, therefore you may want to investigate which "look" you prefer.
The Vignale coach work was definitely not as exciting as Guigaro's Ghibli, especially the bulky rear hatch. The Indy nevertheless is a fun and powerful car to drive and a very usable Maserati. Access to the rear sets is not as easy as a Quattroporte or Mexico, but the rear seats are comfortable once seated.
The steel body on the Indys tends to rust more than other Maseratis and I have seen a few examples with extensive damage. The Indy remains a rather unpopular example among collectors and can be bought at a very reasonable price. Just make sure to buy an excellent example since restoration costs may be even higher that a much more desirable Ghibli.