i believe the 10w-30 mobil is on sale now at certain distributors for about $85/5L. i'm going to try it out for my next change.

up till now i've been running around with castrol formula R 5w-30 with no complaints.

mobil1 semi synthetic 5w-50 and shell helix ultra needed about 1000ml added every 5k km. the castrol usually needs about 500ml in the same period.

i don't know what the deal is there, but i feel better about using the castrol.