Based on how they are made and our test data on the Raptor, it will be quietest. The other is made like the popular chambered mufflers and nothing is louder than them, typically.
the thrush chambered is an exact copy of the super 40...theres no more patent on the flowmaster anymore, so thrush copied it, and voila the thrush chambered...I heard that muffler tested before on the dynomax exhaust tour, and it sounds good!