The fuck is with that guy?
Oddly enough I was just looking into this myself for fun. There is a company that makes them, if I remember right it was about $1300 for the setup for an AI. If I can find the link again I'll post it up here.
Edit:
Here. I know nothing about this company and looking at the price breakout it may be like $2400 with suppressor and barrel.
www.suppressedarmament.com
Edit 2:
Damnit now you have me going down the rabbit hole. It's with subs but it's quiet.