Sound insulating engine room

SV Camino HC33, We are having our engine pulled out saturday morning. I need to replace all 4 engine mounts and do some maintenance on the heat exchanger. Figured while I was doing all of that I would just go ahead and pull the engine and re-wire, re-plumb, paint and sound insulate the engine compartment. Any suggestion on what type of insulation wouold be appreciated? Also considering installing a 12 volt blower to help remove the heat from the engine room but cannot figure out where to vent it outside the boat? I dont really want to bore a big hole anywhere that water could get in? I am not even sure if this is nedded?