Rocker arms

Total waste of money unless you don't have any stock rockers you can use. Little reduction in friction. Ratios are usually all over the place.

Yes I have used them... I have ductile iron and T&D for my race motor. I'll use stock ones on my Gen III Hemi if they work OK.

The cast Mopar and Crane rockers are good. The others are just shiny.

YmMV.