When I had my 156, a misjudgement
by a neighbour's son whilst reversing resulted in me needing to replace the front bumper and lower grille. At the time, somebody was advertising on ebay a set of lower grilles (main central one plus the 2 little ones in the 'holes' alongside the foglights) in stainless steel.
The whole lot including postage was about half the price I had been quoted (admittedly for a new one from a dealer) for just the main grille in black plastic. "Great" I thought and duly sent off the dosh.
So what did I think of the finished result? Let's just say that I was on to an Alfa breaker's yard a couple of days later sourcing a black plastic one. I just felt that it was too much silver and made the bumper look like one big solid lump.
Instead, I ended up just painting the foglight surrounds, doing the Scudetto grille effect (horizontal chrome strips) on the shield grille, GTA-ing the headlights and fitting the Carcept lip spoiler that you can see in the photo below as my attempt at being 'individual'.
Whatever you choose to do, remember it's your car to do with as you please. Just enjoy it.