Dumps are always louder than a setup with tails, and they do seem to have a bit more bass that way - maybe the acoustics of having the sound exit under the car and resonate throughout the chassis, I dunno. But they're impractical on a street car ... not to mention unsafe. Carbon monoxide fumes recirculating into the interior? No, thanks.
Besides, aside from GT's, a Fox with dumps always looks like it's missing something, like its owner was too cheap or too lazy to finish the exhaust. Stainless or chrome tails are one of the things that make a Fox unique. Those long, shiny lengths of steel sticking proudly out the back are almost a trademark of the Fox Mustang, whereas all the other years got short little chromed tips (or almost nothing visible at all).
FWIW, every muffler I've ever had on a Fox without tails has droned like a mofo. Flowmaster, MAC, Pypes ... hell, even Dynomax Super Turbos will drone if you put 'em on without tails.
Get some Dynomax 2.5" tails in stainless or MAC 3" tails in chrome and finish that exhaust off properly.