Good questions.

OK - the "Blends" have less than 30% of even the Group 3, so they are mostly Grade 1 or 2...so, the Group 3's are better oils.

The auto manufacturers tend to specify the oils if they wanted synth...like my wife's Mini Cooper says to use Mobil1.

I assume that following their reommendation would cover you from a warrenty perspective...and that using Reline, etc...would be defensible.
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- TJ

2001 Xterra '03 VG33, SE 5 spd, 305/70/16's, Revolvers, UBSkidderz, Doubled AAL's, 3"SL/2"BL, winch/bumpers, skids, sliders, OBA, Snorkel, pine stripes....

Friends don't let friends drive stock.

http://www.gifsoup.com/view/501230/tj-tackling-crawlers-ridge-o.gif