Mostly want it for sound and also because I plan on tuning the car so I wanted to get the intake alongside the full catback exhaust system.
Do the tune 1st. Most, if not all will not need/require any change to the air intake. Very few will need any change in the exhaust to increase performance. Down pipes, headers will be/are more beneficial.
The Mazda 2.5L and the 2.5L Turbo have the same intake and exhaust. They are both very efficient. Yes, they both have more to give because Mazda (and every other OEM) leave a little on the table for (engine) safety and longevity.
I have tuned my fair share of BMW's (only one actually) and four AMG's, Super Charged and Turbo'd Engines. To achieve their Max gains intake and or exhaust were down at the very bottom of a long list of upgrades to increase performance. Same with my 3.5L TT F150.
Sadly, other than OV there are very few tuner options with Mazdas. Unless you're just wanting to run the 1/4 mile drag, on a race track you could probably make the car faster by upgrading the suspension/tires and brakes rather than trying to eek out a few extra HP.
I'll certainly not argue that the intake and exhaust won't make the car look or sound better, just don't expect any real performance gains especially compared to the money spent. Most important thing of all, this is your car and your money. Do what makes you
happy, not what others think you should do.
I'd sure like to see others chime in here for their experiences and opinions. <img src="http://forum.mazda6club.com/images/Mazda6Club_2014/smilies/tango_face_smile.png" border="0" alt="" title="Smile" class="inlineimg" />