As anyone will tell you the silencing ability is really pointless,but what it does do is incredible.Im a tech here in Texas and what these do is mainly reduce the shock of energy being delivered normally to the cylinder head.I own 5 KWA M4/M16's and all have this piston head, due to the intense rate of fire and increase spring tension,these heads reduce the shock to the Cylinder head,which transends to the rest of the gear box,also the majority of heads I have purchased seem to have a better seal,therefore not demanding me to put such a large spring in my gun to achieve what I am desiring which also helps take stress of the piston and gears.Overall there is a slight sound change but there is a great deal of change in shock when fired,some may say they like that shock,giving much more of a realistic feeling such like a gas blow back,but their gun will not last nearly as long.
Increases longevity and durability as well as performance greatly.
Usually increases seal which increases the FPS due to more air volume per shot.
Great quality and materials.
Pricey but very worth it
Usually cant find just the Piston head just by itself.
It will eventually have to be replaced unlike a aluminum head,but not to any degree of quick.
Evike does have a cheaper one,but its a piece of crap,horrible seal.Stick with systema.
P.S. Make sure when purchasing you make sure which one you want,they make both a Bore-up and Non-Bore-up.Never have I used the bore-up.