The manual says "4 star" and the J117 says unleaded so it is pretty clear that the original recommendation really was 4 star and not unleaded.
And presumably if I used unleaded I would gradually wreck the valve seats.
So what's the difference between LRP, unleaded + additive, and real 4 star?
Obviously the technologies are very different - which one should I go for for economy and long life? Presumably "4 star" is the easy answer, but not always easy to get.
I'd be grateful for any advice, thanks
Luke