Oil and filter for boxer.
This subject has probably been done to death but nevertheless I'd like some opinions.
My last oil change I used a Purflux filter and "no name" (supermarket) fully synthetic 5w40. Now that may have been a mistake as recently I've seen original Alfa filters recommended(they're supposed to have some non-return valve which you don't get on others) and a good brand semi-synthetic 10w40.
Having said that my oil stayed clean for 12 months (I don't do a lot of miles) and has just started to go a bit dark. The engine uses a bit of oil, but no more than a cupful every 1000km.
Alfa33 QO 1984
Alfa33 1.3i.e. 1994