I will be switching to another oil soon I think for longer drain intervals. I just took a job where I'll be doing 70 mile per day commutes to rural sites in Alabama. (~20,000 miles per year) Right now I'm using Valvoline 5W-30 Synpower with great success and very low wear, however the TBN is only showing a max drain interval of 7-10k miles. I'm looking for a 10k-15k capable oil and I'm considering the following: 1. Amsoil SSO 0W-30 2. Castrol Edge 5W-30 3. Mobil 1 5W-30 EP Any ideas on the new Edge? The amsoil is a bit pricey... Also - the Subaru has a 5qt sump. "Now that's thinkin' with yer dipstick jimmy!" Also as a side note - anyone tried 5W-20 in the 2.5L subaru engine? It's not spec'd for it but I am curious if it would help with the fuel economy.