I agree that the cost per HP for a roller rocker on a stock engine would be too high - but that won't stop buyers who are simply looking for something to do without a complete R&R!
The rocker is far more valuable for racing, where lack of lift + the flimsy construction of the original make a quality replacement a "must-do", rather than a fashion accessory.
Take my word for it - just because the rocker doesn't actually disintegrate under high RPM and 300 lb. springs doesn't mean that the valve is tracking pushrod and lobe motion accurately. With the stock rocker, a portion of that hot cam never reaches the valve, and another part gets there at the wrong time.
