Originally Posted by myrt1987
I think the M1 vs. Subaru engines has to do more with the wrx/sti high compression engines.
I was planning on only using walmarts M1 long term as well, until I found kendall 0-w20 (which has almost identical specs to amsoil) for even cheaper then the M1.
Im sure any 0-w20 is fine with a regular oil change interval.
Kendall, that is a name I have not heard of in years. Back in the 60's and 70's that was THE oil, stuff was super slippery. You could take the entire oil line up at Vanidersteins speed shop, put them each in their own cup and using the three finger method find the kendall every time, stuff was slipperier than astroglide, you could probably use it for that in a pinch too.