I have read here on these forms that the stock exaust on these 8s is actually pretty good. And so with that question is their any benefit when running a greddy kit to a catback? Since the turbo is already going to be restricting the exhaust a lot how limiting is it to run the stock exhaust. I love the way aftermarkets sound but I don't really like the Police Officers Attention.

If your state allows it take it off. Better yet if the guy doing your ispection is not a dick take it off. My car runs 1100-1200 F and the cat will be the first to go. I run the mazpsort stage 3 kit and it get hella hot. Take it in consideration! I also have the magnaflow exahaust (straight).

the heat is going to fry the cat. take it off. the turbo will muffle the sound of aftermarket exhaust too.

With the turbo the exhaust is going to be a lot quieter. Mazdamaniac and I have the same exhaust. Mazdaspeed V2 and no cat.
But I don't have the turbo. And his sounds like stock compared to mine.