Probably one for the Motoring forum, but it never seems to get much traffic (badum-tish)
This may have already been done to death, so apologies if it has, but is it worth putting in the more expensive "super" grade unleaded (or Diesel, if there is such a thing?) in an Insignia?
I assume (rightly or wrongly) that they are aimed at more high performance vehicles and wouldn't give much benefit versus the extra spend.
Thoughts?