I changed the air filter to a new OEM, new oil is Millers 5w40 (I think old oil was Selenia 10w40) with OEM Alfa oil filter. Tyre pressure is checked before every motorway journey and kept at 2.6 all round.
Thermostat - it warms up quite quickly, stays constantly at 90 with no need for the fan to kick in so I think it's ok but I might well flush through and put in new coolant.
Timing - hadn't thought of that. Will see if I can get a local specialist to check it with a timing gun.
Others have mentioned "lambda" to me - no idea how to deal with that but wouldn't the engine management system warning light show? I've also wondered about the injectors and exhaust cat system - in other words, in old money, the "mix" and I would have had a screwdriver on the Dell'Ortos to sort it...dream on.
99teki - forgive me, I'm not following your suggestion.