Shep76, if you want performance with QUIET, here is my solution :
Get a muffler with the proper tube size for the application (engine size and power) then get the BIGGEST, FATTEST, LONGEST muffler that will fit under the car.
NO 13" case muffler will be quiet (except maybe a 1 1/2" pipe version)
I have a 28" long fm with a 22"case on one of my cars, and a 26" case magnaflow on another.