Quote Originally Posted by docjames View Post
I have never put anything other than BP ultimate in my MkV - it is refined to the higher octane rating, then has cleaning additives added.

The others are refined to slightly better than 91, then octane boosting additives added, then cleaning additives added.

In theory, all are 98. I know which one I prefer.
A good analogy is BP Ultimate is like a premium fast food (grilled and fresh) like Nandos/Oporto whereas Shell and Caltex are more like your McDonalds/KFC (fried and frozen).

Both may be similar products but one is better for you, goes down easier, gives better performance and exits cleanly.