ahh, that is actually a 2.25inch pipe in/out for the muffler and resonator is also 2.25inch, the tip is 4inch. that is the right size, pretty expensive set up, for just something basic, not even a new cat going on there. But this is for sure the right size for the car, you could have probably gone to 2.5inch and still been ok, but they know what they are doing, so its good.

http://www.magnaflow.com/02product/s...e=Sport&id=228


Mazda 3 Cat-Back Exhaust System




PRICE: $634.63
YEAR: 04-06
PART #: 15861
DESCRIPTION: 2.0L/2.3L I-4, Sedan/Hatchback, I/S,
rear side exit,
4x4x14" p-SS resonator, 2.25" SS tubing,
4" rolled/slash/p-SS tip



Additional Information
All Stainless Steel, Mandrel-Bent, Cat-Back Exhaust System With Polished Stainless Steel Tips.

 

heck, anything over 2.5 is setting it up for a turbo... and if no turbo or supercharger... then you are just asking for a loss of compression and loss of hp/torque

 

heres a cool video of the 3 with a magnaflow, best sound yet

http://video.google.com/videoplay?do...43&q=mazda+2.3

 

2 questions. 1 how do you tune it before the ecu goes back to default and does anyone know if Magnaflow or Borla would be better? Thanks.

 

Magnaflow is better, to me Borla seems to suit muscle cars and trucks.

 

Tracker, how do you tune your car after adding intake/exhaust? You mentioned it above. Do you have to buy a programmer to plug into the harness or what? And if so do you recommend any? I would rather be sure than guess. Thanks

 

?????, well from what i understand the Mazda 3's ECU is very complicated not only yo get to but to reprogram, i dont know exactly how its done but ive heard that there are a few aftermarket companies that are working on it and i dont know if any have been put into production, thats my guess for more or better info id ask somebody like babyhuey, 6pack, or michael91077. If i find anything and if i remember to about it ill post the info.

 

actually i know nothing about being able to tune the ECU. from what i have read the ECU will actualyl re-learn its settings if it is tuned, like using a chip or some kind of plug-and-play performance mod they sell on eBay, The ones you plug in between the ECU and the engine, they say they add so much horsepower but are selling for $20. You get what you pay for, buying one if those is trouble really. A real chip or Hyper-programmer that is sold will run at least from $150-$500 range, and those actually provide an enhancement to performance. As for getting an CAI and exhaust, there is really no wy to tune those, except for where to place the filter of the intake and muffler on the exhaust. when you get into turbo's is when youwould start going thru tuning and running on the dyno.

 

well i finally got it in a full Magnaflow exhaust and at a discount, if i get time ill post a sound clip

 

Sounds good, you gotta hook up a sound clip on it so we can hear it