Hm... Amsoil ASM 0W-20 with an EaO23 filter to bump up oil capacity to 5 quarts run for 15,000 km could be interesting. Never been into extended drains, but if I get a UOA done on the current oil, use a good filter, and the ASM which seems to bottom out grade wise at 8.5 cSt would be really good, and the logic in my mind behind it that the total cost of running GTX 5W-20 or Pennzoil 5W-30, and a Wix filter for 5000 km amounts to the same as running ASM 0W-20 with the EaO23 filter. The longest OCI this car has ever seen was 6200 miles (unintentionally) with Pennzoil 5W-30 and a Wix filter, and that oil came out pretty tired but I didn't think at the time to get it analysed.
Might be an interesting compare and contrast type thing...I just don't put on enough miles to get everything done with this car I want to try out. I want to UOA my current fill of Mobil 1 at 5000 km, I want to run a cycle of AutoRX to clean out the engine, and I want to try 5W-20 to see if I get a mileage improvement or see no wear change, then if that works out I want to try 0W-20 on an extended drain to see if I get any benefit out of it. But of course, by then, what I have spent on UOAs will probably claw back any savings I ever make.
I have been BITOG'd.