Reason I ask is that I just bought my '99 Camaro Z28 from a dealer as a certified car. One of the things they did before putting it up for sale is put a new stock exhaust on it. Since I know the pipe is brand new (the sticker is still on it), is it really worth the extra money to buy the 3" cat back?
Also the reason for upgrading the exaust is not so much for the extra power, but the sound. They did not put anything on for exhaust tips either, just the pipes stickin out.
And if anyone kows of an exhaust that has a low rumble at idle but not too much drone cruising feel free to mention it.
It also came with Hooker headers that use the stock cat's. Not sure how much that will affect the sound with different mufflers.

 

check out the Dynomouth exhaust... I have the exhaust, nice low rumble @ idle but screams like a banshee @ WOT.. goto google and do a search for dynomouth and look for ratio411's site... He has information and soundclips of DM... Sounds great in my opinion and will not cost you an arm and a leg for it either...

 

It's not the extra 1/4" of diameter that makes it sound different, it's the muffler that comes on a catback that is responsible for that. I don't think you'd even be able to tell the difference b/w a stock pipe and just a 3" pipe as long as it had the same muffler. I know for a fact that the stock intermediate pipe is good for over 450 hp. Jordan Musser on the board kept his i pipe stock and was making a good deal of hp.