yes it does...if you follow the air intake, there is a hose that feeds into the shutter box to bring warm air into the intake on the cold winter days.
That brazed 45 you are talking about should have a standard 1" NPT thread on it, you can just use 1" pipe fittings and do whatever you want to do. However, keep in mind that those fittings coming directly off of the muffler are stainless steel, and are probably not brazed on. But as mentioned, an additional muffler isn't going to do much good.