When considering any mod, I think it is wise to take as small a step as possible on your way to your goal so that you don't wind up with throw away mods. If you go with a Stinger first and find out that it is too loud then you may have to replace them with something else to get to where you want to be. Try the LT's first and see how you like them with the stock TI's and then if that is not enough go for a catback.

Just my .02 worth!