If you're considering the buying the Livernois/Corsa catback system for you XSport, I recommend buying 9Sec's system here. I didn't, and now I wish I would have. I bought mine from Livernois; I didn't need 9Sec's extras, and didn't want to deal with changing the tips. But I installed my Livernois system yesterday, and the WOT raspiness is driving me crazy (nice rumble at startup & idle, though). so now I just ordered the same Vibrant resonators that the OP has, and will have to get them welded in. I could have saved a bunch of cash if I had bought 9Sec's system.
Could be placebo effect, but it does seem like performance has been improved. No numbers yet, though. I do have PPE catted downpipes as well, which were installed previously.