not much change yet at idle but with the huge resonator before the muffler it is hard to say if a performance muffler will even make a difference. I plan on replacing the stock muffler with one from MagnFlow (they have a single and dual outlet kit for the 2011 Cruze already and their website has sound clips of these kits). The kits from MagnaFlow range from the mid $700 to upper $800 range. I have around $125 in the work done already. If replacing the muffler doesn't give me the sound I want I may opt to remove the resonator (as with the MagnaFlow dual kit). Here is the MagnaFlow site http://www.magnaflow.com/02product/shopdisplayproducts_cars.asp?make=CHEVROLET&model=CRUZE&year=2011
...something to remember, the turbocharger itself acts like a spinning "muffler" to exhaust pulses because each pulse must pass through the spinning turbine blades before it gets into the head-pipe. That tends to "chop" the peak exhaust pulse pressure up into many smaller pulses, which tends to moderate a growl into a purr.
I did exactly the same mod on my Cruze. Did it for looks, as I haven't changed the muffler or resonator. My car is Granite black and the chrome tips (just like yours) really look good. I had the muffler guy extend my tips out a little further than yours.