There have been a number of attempts, some have had luck pulling the pancake and replacing the resonators with real mufflers.
Otherwise it seems that the Corsa (also sold by Jeep) is the only one that does not drone. Some think the mufflers hang down awkwardly, however.
Do a search for Corsa, Borla, Flowmaster, magnaflow and you should be overwhelmed with ideas. It is a common discussion here.
Exhaust sound is subjective, and what sounds great to one is annoying to another.
2011 Grand Cherokee Overland V8, 2009 Liberty Rocky Mt V6, 2000 Grand Cherokee Laredo I6, 1979 CJ7 I6 Quadratrac