How much hp can I get?

[Kuro3]

Hey fellas. I have presently have a 3s 4dr with a simota sri on it. How much more horsepower can I get from the the engine by putting a good exhaust on. Also, are there any exhasut recommendations? I don't want anything too loud, you know that'll like rattle everyone's bowels as I drive by or anything or give me headaches on the highway, but something with a nice note to it and gives me as much hp as I can squeeze out with an exhaust system.

Thanks

 

[tsunami]

the vibrant or borla are probably more some of nicer sounding quiter ones (imo) and the the vibrant gets more hp gain due to the high flow cat. prob 7-10hp or so with an intake already the borla is probably 6-8hp. also a lof of people like the draxas exhaust as well you can get it with a highflow cat, cat back, or race pipe set up. there is a group buy for vibrant header and exhaust going on the other forum now... www.mazda3forums.com

 

[RHAGEL]

I am looking for a quite(er) exhaust and I have my eye on the Racing Beat and Ark. The Ark looks damn good!