Every vendor here gives his/her opinion at one time or another,and it coincides with the content of the question.I think Comp/syn did a very professional unbiased job-information wise and personal decision wise. Who else so far has given as much info?.Also,he did answer the WallyWorld/Amsoil question. Its all about base stock.Read up. Chris. Note:I use Diesel oil,so I have no gain here,just opinion.