flows vs. catback
"Flows" = flowmaster. Unless you are running duals, you will have only one muffler. In this case you could call it a flowmaster or hooker, or whatever brand you get.
A catback systems is the piping from the Y pipe in the shape of an I back to the muffler and out through usually dual tips. Go here http://www.ls1speed.com/catagory.cfm?catagory=exhaust and scroll down a little more then half way to see it for yourself. Hope this helps.



