I'm afraid you're being strung a line there, if it available then anyone can buy one, if the dealer has told you that they are the only ones able to get it then they are lieing through their profit generating teeth.
To lose one bank is normally an earth failure to the coil packs or injectors on yours, have end to end checks done on the engine harness.
Indeed I have, most folk know me for my Alfa knowledge, but as many systems are shared on the Ferraris (I do work on all makes btw) and there are a few I look after in my area, Iv'e been fed that BS by parts guys in a few dealerships, but getting the part number and cross referencing it myself I have never failed to obtain the item at generally 1/2 the stealers price.
It is like lot's have said many times, car manufacturers use other manufacturers to make up a considerable percentage of every vehicle, then charge ridiculous prices for things that they do not make but put their name to..!! Go to the actual manufacturer and save a small fortune..!!
Agree with your point of view hodroyd. What does Maserati actually manufacture? Still have to proceed with caution because they can carry out slight modifications that can be overlooked with disastrous consequences?
Trust me guys I spent a lot of time researching on the net for my ecu's for the 360 and I decided that the genuine route through the dealer was the only way.
Can't believe F1 teams buy there stuff off ebay or nip down to Halfords.
Plus the boxes they came in are pieces of art.
Phil.