fastest full bolt on n/a 3 ive come across (including lightened flywheel, clutch, crank pulley) ran somewhere in the mid to low 15sec range for a 2.3l. Yes that 2-7 is hp/tq, but those can be higher if a hypertech unit is added into the mix, also things like a lightened pulley and flywheel make a huge difference in how fast the engine revs.

Ownez if its noise you want then its an exhaust you need

 

Yes I think the Magnaflow muffler would do it for you. That'll free up some back-pressure which should not only offer a little more upper end power, but give you the noise you are looking for. If you have anything left over, you could get a nice 3"-4" double walled tip for the system and have that installed too. It would still be cheaper (and probably just as effective) than buying a cat-back off the shelf.
For what it's worth, a little more noise was one of the things I was after too. I too thought the OE system less than sporting and wanted to be able to hear "the engine talkin' to me," as well as hear my shift points better. The Vib system is a very nice piece, but quite expensive and probably not worth the money.

As far as tigermack's car goes, he is cat-less and lives in California. He has to put his car back to stock specs twice a year (every 6 months) to get it to pass California emissions testing. Since the header and loss of the cat are probably the bulk of that +/-20hp increase, you have to run illegally most of the time and run the risk of having the po-po find out about it. In Cali, and now 15(?) other states that have adopted CARB emissions testing.
Changing your exhaust twice a year, including the manifold doesn't sound like a whole lotta' fun to me. I'll stick w/what I got, for better or worse. And if I need more hp, I'll buy something w/a V8 in it (over my wife's dead body, of course.)

 

so what i have to get is a new muffler or muffler tip for the sound?
and will the muffler or muffler tip make the sound or does that mean i have to get a new exhaust system?

basically.. is there a difference between muffler and muffler tip with sound

 

there is a huge difference between a muffler and a muffler tip but there are different types of both but you dont need to know the details. All you need to do is change the muffler but you can change the whole exhaust as well

 

1) No, I wouldn't change the whole exhaust, or go to bigger tubing. It is,m in my opinion, not necessary in your case. Plus you might lose additional low-end torque by doing that.
2) Go to http://www.magnaflow.com, or http://www.vibrantperformance.com and find one of their universal mufflers that will fit 2.25 - 2.5" tubing.
http://www.magnaflow.com/02product/02muffler.asp
http://vibrantperformance.com/catalo...1022_1031_1110

You might also look for, and this is only a suggestion for another look (appearance mod, if you will) a nice exhaust tip to add on to the stock tailpipe that will look better.

http://www.magnaflow.com/02product/02tips.asp
http://vibrantperformance.com/catalo...Path=1022_1034

Have the new muffler installed in the stock location UNDER the car, not hanging off the back like some Honda ricer. If you choose a new tip, the shop will remove the stock tip and replace it with the new one using the OE tubing.
You are not liable to gain much hp/tq from this set up, but it will give you that sporty sound you want.

 

are mazda 3 mufflers offset-offset?