If the G17 and G18c share a barrel, then check Evike for Guarder barrels, in silver and black. The King Arms AAC is probably the most realistic pistol suppressor you can get.
The prices put forth were speculation by another member simply stating that that would be the maximum price HE would pay for them. The official prices have not been released yet, but we should find out soon enough.
Dupont makes the polymer*