Need Advice on an Alfa Romeo Giulietta QV

Hi Guys,
I badly need some advice about a Giulietta I want to buy. It is a Quadrifoglio Verde and the current owner states that it is one of the Maserati Editions. I highly doubt that, because there were like 100 of these ever made and only for licensed Maserati garages. I even contacted an Alfa garage to ask for it and after giving them the chassis number they told me that the first ever owner of the car was a private person and not a garage or something like that. I'm pretty sure this is a sign that it is a normal Giulietta QV, despite having an all brown leather interior and even the Alfa for Maserati plaque. Can you guys help me finding out if it really is one of those rare Maserati Editions?
The chassis number is: ZAR94000007125015
Also, it has nearly 150'000 km, the timing belt, water pump and spark plugs are overdue.
I also read that with this specific model there is a pretty good chance that after 150k-200k km I could get serious problems with the gearbox and the Turbo, is that true?
Thank you guys!!