Well,
My Turbo performs according to the handbook - the gauge may drop slightly below the 2 bar mark (literally, the second line on the gauge) with the engine hot and idling. At other times, the gauge stays around the centre.
Knowing how these oil pressure senders work (or, more to the point, how they don't work) I would say that you have a 'tired' sender, like my Alfa 164 has. They are quite capable of reading fine with the engine cold, but very low once the engine has warmed up - the actual pressure does drop somewhat (as Chas says) but nowhere near as much as your gauge would suggest.
This is probably the reason why you have an oil temperature gauge kindly provided by FIAT - so you can see if the oil is hot, and therefore if it's fair to expect a pressure drop. During a track day with my Uno Turbo, the oil temperature is frequently over 140 degrees (C, of course!) It would be nothing unusual to expect a pressure drop at these temperatures. If, though, you have the pressure drop with the temperature gauge hardly registering, it's more likely to be just the sender.
I recall that a common fault is that a seal inside the sender leaks, causing the housing to fill with oil. Since oil isn't compressible, this leads to the gauge under-reading because the diaphragm can't move properly.
To fix this problem, you can try drilling a small hole in the top of the housing, to let the excess oil out. This may either fix the problem with no noticeable oil leak, or, at the worst, you'll have a small oil leak from this new hole. It has to be worth a try, but what I can't tell you is where to drill the hole: the senders have several different designs. I'd try on the end surface, opposite to the electrical terminal.
Steve is right in that, if there was a problem, you would have known about it by now.
One other thing: oil flow is just as important as oil pressure, and it follows that if the oil pressure is low, the flow may be still strong. If the oil pressure was over-high, that would probably be worse because it would suggest that the flow has become restricted!
But perhaps, next time you change the oil, you might like to use a 15W50 like I use: now that it's summer over here and the daytime temperatures are unlikely to fall below 24 degrees...
-Alex