Planning to kill someone? 6 blocks is really pushing it for a .22, especially a handgun.
Most .22 handguns, including the Mk II handle high velocity rounds with ease. The bests IMO are Velocitors.
I believe the suppressor for the Mk II can be fitted to a Mk III, but some fitting may be required.
A suppressed .22 handgun automatic is ~ 50-60 Dec. This is including the air exiting the muzzle, the slide cycling and the empty casing ejecting. Using subsonic ammunition, such as high velocities, makes it even louder.
I'm pretty sure the gun on the site is all stainless.
Hope I helped. Don't consider me an accessory.