Not that much. Ur gun is designed to run on co2. At most u might have a o-ring or 2 go bad.
HPA is worth it if u play enough, and really want a higher end gun. Or if u care about consistancy and not having drop-off from a co2 tank.
Nothing wrong w/ running HPA on a silver bullet. Hell i use a halo and HPA tank on my old electra
