I have a 2012 Mazda 3 hatchback and I'm looking to give my exhaust some sound. I was thinking about deleting the muffler and replacing it with a 2.5 pipe. I'm also looking for the most least expensive way, and I think removing the muffler would be my best choice. Everything on my car is currently stock. What do you guys think, should I delete my muffler?

 

If you do not have a muffler installed on your car in California you WILL be given a ticket, Section 27150 VC states it is mandatory to have one installed on your car. Section 27151 VC prohibits the modification of the exhaust system to amplify or increase the noise emitted by the vehicle, making the vehicle not in compliance with Section 27150 VC or exceeding the noise limits established in Sections 27201-27206 VC. Section 27151 VC does not prohibit all modifications to an exhaust system. It also does not prohibit all modifications that increase the noise level of the exhaust system over that of the original, factory installed exhaust system (as it did until 1980) It only prohibits modifications that result in a noise level higher than those specified in Sections 27201-27206 VC.

In other words buy a new muffler that is CA legal and louder for you, do not just take it off unless you want to risk getting a ticket over your car being too loud.

Also CA law states NEW cars have to emit no more than 80db sound at 50ft under full acceleration, although I dont think this part is enforceable against the public since it is under the dealership part of the section.

If you want to try your luck go for it, I wouldnt, they also might fail you when you smog your car (whenever that is in Cali).

 

To get a little better sound, Mazda usually offers a "Mazdaspeed" cat back. It is a step up from the stock exhaust, slightly increasing the diameter and has better bends for better flow. The beauty about it is that it has "MazdaSpeed" Stamped right on (bottom of muffler and on side of tip).
You drive a Mazda, right! No tickets!

 

If I got a speed3 cat back, would there really be a noise difference?
I'm looking for a nice rumble

 

Talk to your local Mazda dealer if they offer an upgraded cat back (if you dont already have it)