Lots of great feedback in this post! The only thing not touched on is the valve seats. And it's quite simple. Alfa valve seats are already hardened so nothing needs to be done.
US Alfa owners have been using unleaded fuel for 30 years with no ill effects (exept perhaps for the drop in octane over the years
).
An Alfista could tell the difference between engines in a nanosecond; the 2l has a spin on oil filter, the 1750 doesn't.