Flowmasters are good and all but the problem is that everyone and their baby mommas cousins pet dog has a set. They're also prone to droning during highway driving. Still, if you're looking for the old school muscle car, you can't do better than some Flows and an H pipe.
Now, if you want to have a sound that's still sick that not a lot of people have, I recommend an X pipe. X pipes scream at WOT and have their own distinct (but still badass) sound. Some are raspy, some are not. But they all sound somewhat "exotic" and if that tickles your fancy, then I recommend checking them out.
If you're looking for sound clips, check this link. By far the best site I've seen for 5.0 exhaust clips. Now mind you, take what you hear with a grain of salt. Things clips are RARELY a complete representation of what a car actually sounds like. Examples of why include: you don't know what kind of mic or camera recorded the clips and how great of a quality they are, you can't really tell if the sound is echoing off other surroundings, and on most of the clips, you won't get an idea of how the car sounds when you're INSIDE the car.
Still, all negativity aside, they offer a glimpse of 'subjective' sound that a car will have with a given combination.
Link:
http://www.donjohnii.com/Pages/Exhaust_Clips_Page.htmlAnd lastly, X pipes will free up a tad more horsepower when compared to H pipes due to the X pipe has a better scavenging design. Don't get too giddy, because it's highly unlikely you'll feel a difference. Mainly go for either an X or an H based on the sound it produces.
Just to throw it out there, here's what I'm most likely going to do with my car.
BBK LT's, Dr. Gas X pipe, Spintech Sportsman mufflers with tailpipes. Should be sick as hell.
