!! help !! muffler choice and installation

Hey fellow WJ owners. Ive got a 2000 WJ Limited with the 4.7 liter v8 engine. Ive been thinking about getting rid of the stock muffler for a super 40 flowmaster muffler. What im looking for is a beefier sound that you can hear from down the road. If anyone has replaced just their muffler for a performance one i'd greatly appreciate your input on what to buy and the range of labor for installing it. Thanks