Up-date...
So I went to mazda, the service guy looked at the cracks. Said it was a common problem with the oval shaped exaust, the metal that over laps to form the 'lip' isn't thick enough. So he ordered me a new one. 10 to 14 working days, bah, I could wait. Plus its FREE. So any of you guys that notice small cracks on the muffler tip, go to mazda, they will replace it with a better sounding one for free!!!