What mods does it take to install these and what are their benefits.

Can you tell me more about the set-up. So this is only a roller rocker system not a full roller cam deal? Anything you can tell me would be more than I know. Thanks

EDIT: Ok so if Im not mistaken the point is to get the valve to open further to allow more air/fuel to enter, is that correct? So it sounds like your gonna have to have a piston that either pretty far down in the hole or some pretty big valve reliefs so wouldnt you be sacrificing compression?