Thanks for the posts, think I'm getting there.

So it seems like either Quantum IIRC or Shell Helix Ultra Extra is the best, and also Castrol Edge 5w-30.

I agree with all, the best oil is the best choice, just a few last points:

Firstly, my car is 1998 S8 137k miles.

- Older cars get mentioned for different oil compared to newer cars, what the reasoning behind this?

- I've looked on Opie Oils and found the Castrol Edge 5w-30, does this sound like the best buy for me? If not, where's the best place to get the best oil?

- Is 5w-30 better than 10w-40 for my car?

Thanks again

George