This car is an 84 which means that it has the Salisbury differential which is very dangerous when it goes bad. The splines that connect the driveshaft to the differential will wear out, and when they do they will cause the rear wheels to lock unexpectedly. This is also very expensive to repair.
Also, Maserati had no idea that people would use the air conditioner so much in the states, and it is a major problem point. If it is ran for too long, the extremely fragile fusebox will not be able to handle the extra load, and it will melt. It can also cause the water pump bearings to seize, and the timing belt will break which of course means an engine rebuild.
The turbos do not have intercoolers, and are designed to be cooled by the engine oil. I think you can see what's wrong with that. With non-synthetic oil the turbos will probably last only 15k miles. Replacing the turbos= $$$$ so synthetic oil is mandatory. A sign of bad turbos is black smoke coming from the exhaust.
The oil galleries leading to the cam housings had small bronze filters that will clog and cause the cam bearings to seize. There was a recall for this back in the day, but many still have them.
You also need to replace the valve shims every 10k miles or so (I think). This is EXTREMELY difficult. All of them have to be perfect because the two intake
valves are operated by the same cam lobe. This job will take a pro 30-40 hours of labor. Seriously!