My personal opinion on mods is not too much on the outside. What ever chips, exhausts etc you put on/in are all fine. BUT lets never detract from the Alfa beauty of the original car or make it out to be some other Alfa which it isn't. Unless the change is real in the sense of looks, handling and performance.
I certainly don't like Saxo's, Fiesta's or even more so VW Golf's looking over the odds when in actual fact it's all cosmetic and nothing inside. I hate noisy exhausts on these cars too, just for the sense of please 'notice me'
It all swings in roundabouts so that's just MHO
BTW Andy - I prefer the black bits on your 155 bumpers