Difficult and really depends on personal preference.
I used to get 5w40 Fuch Titan Fully synth which a decent filter like Mahle or equivalent. Then change every 8k.
Now I do more miles per year and also using LPG.
So I now choose to get cheaper...
10w40 Semi Synth and again a good quality filter but change every 6k miles.
Options though are a wide range for the Twinspark.
5w40 Fully Synth - Best cold protection and overall
10w40 Fully Synth - Good protection and overall
10w40 Semi Synth - Best budget conscious (Make sure it reaches all specs most will)
10w60 Fully Synth - Best for higher Rev protection but lowers mpg (Thicker oil)
Also good for those who burn oil a bit more than normal as the oil takes up tolerance differences.
Its a bit of a mine field with oils. People have their own preference. Budgets etc.
But it boils down to this...
Buy the best filter and oil you can for your budget and change as much as possible.
Alfa 166 2.0 Twinnie - LPG and a few trick performance parts