http://www.bobistheoilguy.com/forums...pics/2804931/1
This thread hits on some of the stuff I read. Mainly, the PP 0w20 vs 5w20 NOACK values. The 0w20 actually has a lower NOACk than the 5w20, likely linked to better base stocks. Conversely, the PU 5w20 beats both.
The shear thing I read seems to mainly apply to w30 vs w20 oils as opposed to the low temp rating.
Cheers
Nathan