just un bolt your muffler and see what it sounds like. I had an old jeep cherokee with straight pipes from the headers. Yea it got a lot of looks but it sounded sooooooooo sick, even though i would have to wear ear plugs some times. Oh the life of a broke college student.
You would have been more happy with a bimmer until you were like, meh, i dont need to eat this week, the heat doesn't need to be on. My point is of course you are going to get some little problems here and there, its a mazda not a bimmer.