For long trips where you are going to spend a lot of your time in the low revs while cruising, in my opinion you won't really reap the benefits of a higher octane fuel. If you are happy with the E10 and reckon you have good results with it, then by all means stick to it, otherwise regular unleaded or premium will work fine. If you are like some of us (myself included) and tend to think that BP Ultimate is good for your engine, then by am means feel free to use that. This is more for the 'cleaning' properties of the fuel and not for its octane.