Ok, I have used RP in the past. Never had an engine failure because of oil brand, but there was a post last year about Brad Penn not lubing rocker shafts and piston pins well. A box of Penn grade 1 is $80, Amsoil $150 and Driven GP $105 , valvoline vr1 $100 to my door. I really would like to give the Driven a second try. Was just curious to what others had to say about the Driven oil good or bad.