A while back I was on the Cummins site looking at the current B-series engine and noticed that there was a factory option that is supposed to reduce engine noise by about 5 decibels. Does anybody know what that entails. I don't mind the engine noise, but it would be somewhat nice to be able to talk to someone outside my truck without shutting it off, or stand a chance of not having to shut it off at a drive thru window :grinpimp: