i gotta chime in also : ). when most people talk about drone on flows they are thinking of 40's or Super 40's cmon they're the loudest muffler they make other than cherry bombs!! Here is a video of my car with super 40's i'll make a new vid with the delta 50's but omg the differene is day and night and they're still flows. YouTube - Mustang Drive By if you want a quiet exhaust note then don't get Super 40's or 40's that just wouldn't make a lick of sense. if you want that glass pack sound.. go for it i guess i switched from stock, to spintec, to flow 40's with no tail pipes, Super 40's no tail pipes, then added tail pipes, then put in the 392 then i got 50's and mandrel bent summit 2.5" pipe. i'm most happy with the 50's. the spintecs in my opinion were crap. my opinion: straight through and glasspack mufflers sound cheap, get mienike or midas mufflers if you want cheap sounding or quiet exhaust. otherwise i prefer the sound of a flowmaster, and i know it will never get me the 5 extra HP i crave every day, but i think the car is still a whole hellll of a lot of fun without it. btw i've never had to buy new flowmasters because mine 'broke' or whatever. i've had flowmasters for years swapping on different cars etc.