Hi vegas1500,
I have the Corsa sport system and love it!
I went with it since I knew I was going to keep my AV for a very long time and I wanted the stainless steel system with a lifetime warranty not just for the muffler but the pipes and tips too. It was a very easy install of about 25minutes at a muffler shop and they only charged about $50 to install.
I would say the decision has to be yours, you will save money if you just do the muffler and get something like a Flowmaster and maybe some fancy tip if you like. That may require more labor to install and it usually is not a lifetime warranty. So if you are comfortable with your capabilities or those of your local muffler shop then you can save money.
You would not be disappointed with the quality or sound with no resonance from a Corsa setup though.