Thanks, thats a bit more to think about. I'm going to visit Ben when I get back from holiday abouts some other work so I could ask him about this too.
I am confused about Castrol, I remember on Tyresmoke there was a lot of oil discussion, one post said Castrol makes Quantum as well, but they gave the opposite advice, that Edge is better than Quantum because of the additives. Confused.
It may not have been on tyresmoke it may have been a post on rs246. I tried to find it but just came accross this post, I think the conclusion at the end was they are the same:
http://forum.rs246.com/viewtopic.php...83919&start=45
Thats the other thing I forgot to mention. I dont know if its a good thing or a bad thing, or even if I imagined it, but since switching to Castrol Edge (from Quantum) I have not had to top up the oil noticibly in about 10,000 miles. With Quantum I had to top up between oil changes.