While different headlights will change the look of the car slightly, I don't think that the change is particularly noticeable, unless you look closely. And while I agree that the Alfetta GTV/GTV6 are nice to look at, Alfas are generally best for driving, not looking at, IMO...
Personally, I'd turf the Carellos at the first opportunity, having experienced the change in upgrading from Carello H4 headlights to a Hella H4 setup in another car.
While it may need different buckets to change the inserts for European/Asian/Australian models, there are plenty of Japanese cars from the 1960's and 70's which had four headlight fronts (Toyota Corona or Crown models, for instance), and in my experience, many car wreckers will give the whole four headlight assembly away for practically nothing. Change the buckets over, put some Hella/Narva/Cibie headlight inserts in, which fit the Japanese buckets with no problems, and....daylight (almost).
The low beam inserts are available either in H1 (single filament) or H4(double filament high/low beam) versions, so you can fit the H1 versions with no change to the wiring, although relays do improve matters, and take the strain off the headlight switch and high/low beam switch.
While the high output bulbs don't last as long, they don't fail particularly quickly, unless you touch the glass with your hands when installing them, which causes them to fail quite quickly, unles you wipe the fingerprints off with methylated spirits or a similar alcohol-based cleaner. However, you do need good wiring for them, and you should consider relays. Unless the wiring is good, they fail much more quickly, according to Hella, who say they are designed to last the longest when operated at close to their rated voltage. I've experienced that myself when running driving lamps which were earthed through the metal bumper bar. After experiencing short globe life,
some experienced rally drivers in the car club I belonged to told me to provide separate earth return wires for each lamp. I wired them up with an earth return lead back to the battery, and the 100W globes lasted for years, when it had been a matter of months previously!
