Yes, they will. These valve springs are made from aircraft quality alloy steels to give the best performance.

We would advise the stage 2 comp cam with standard rockers as we would be able to provide a cam and chip package where as we would not be able to provide any tuning services for the Crow item.

The stage 2 Comp cams and tune package generally provides better "out of the box" overall results then the Crow cam & high ratio rockers combination depending on the custom tune if going the later.

No you don't unless you have a VY model.  Unfortunately, Holden got a bit slack with there casting maintenance when they knew the production run was coming to an end.  This resulted in excessive casting flashes in the push rod holes which tend to run on the push rods unless new 5/16" push rods are fitted when using our 1.9 high ratio rockers.