lcowart

I have a question. I just ordered the roush exhaust for my 2010 gt. I was wondering if anyone here has this exhaust with an x pipe and if so, what kind?Is it really loud and does an x pipe add any horsepower? From what I have read, if you go catless (I live in a state with no inspections) it makes a loud exhaust really loud and they say you should go with an exhaust with mufflers to quiet it down, which seems to defeat the purpose. Just wondering if it would even be worth it. Thanks.