Re: Where to get 10w40 oil?
For oils you're paying for the name. They cant sell it unless it meets the minimum standards so you're fairly well guaranteed to get good stuff no matter what. I always look for oils that exceed the standard, regardless of name or brand.
With the filter there's no such controls. Have a look inside a spurious filter and compare with a real one - there's actually bits left out of (some) spurious ones.
I had a 2.0L twinny let go on me 300 miles into a new filter which is why I looked into it and was shocked to see that they didn't bother putting in a release valve.
Engine lunched itself once I went over 6k rpm. Oil starvation to big ends. Engine was well used to 6k rpm with proper filter before that.
btw engine had Magnatec 10w40 in it when it lunched.