In real life PBS 4 and PBS 5 silencers are used with modern AK's (5.45mm round). Scopes is different story. You can use PSO, Kobra RDS, PK RDS and whole bunch of other scopes, as long as they can be mounted on a side plate. Kobra probably is the best choice. Make sure that threads on your gun match threads on silencer and side mount plate is compatible with the scope. Optics can be purchased from ebay or
http://www.kalinkaoptics.com/