I disagree on the rockers if you can get them cheap enough. I got mine in trade for an old Dodge 360 rebuildable long block. Nice seat of the pants gain, similar to when I put on my intake. Definite mid to upper RPM improvement. Little to no effect on MPG.

That said, I would still rather spend money somewhere else first if you pay retail. Spending $200 on them, I'd rather do exhaust as that was a bigger gain for me.