I know what they are but what exactly do they do. Also if I chose to get some to install on my stock head would it be hard to do and would it be pointless? I was looking at the 1MM oversize ones. This is the info given.

from accordstore:
These Ferrea valves are specially designed for use in racing engines that are subjected to extreme exhaust temperatures with Turbo, Nitrous, or Supercharger. Ferrea valves use a special alloy designed specifically for this application. These valves feature avionics-quality hard chrome along with a specially applied hard tip. The engineering staff at Ferrea spends countless hours conducting flow bench tests to achieve an optimum balance of flow, velocity and efficiency in the design of this valve. As a result, these valves incorporate smoother radiuses and unique undercuts. These exclusive features are what make the Ferrea Competition Plus Valves unequalled in performance and reliability! 35mm head, 5.48 stem diameter, 116mm length and 3.5mm tip length. FITS VTEC ENGINES.