Yeah that's just normal, full price. You can probably find someone selling one on the forum if you're patient enuf. New or used maybe...
I saw it on ebay for 190 or something, but then 15-20 shipping. But no sales tax at least.
Also, fyi: there have been threads on this forum that say that the racing beat cat back has a better sound than the mazda dealer one. Supposedly it's not outrageously loud and doesn't make a droning noise as much...might want to look into that...(?)
Good luck! Let me know what u decide on cuz I was looking for a new exhaust too...