depends if your going to use it for hunting or no
calm down im only joking
most of the gas goes down the spout so the silencer will silence that bit, there will obviously be some gas loss from the breach but you will have to listen to a few people with silenced guns, try you tube if you don't have a club member with one to make up your own mind if its worth it or not.
as Paul said, it will make a difference,
perhaps Nick the resident rohm expert will be on to give his tuppence worth.