Idk i was driving amd was trying to figure out what it was but couldnt -_- but when i drive once i hit about 4k rpms my exhaust makes the inside cabin vibrate with huming it sucks lol i cant really appreciate my exhaust sound i need to buy instlation n put it under my carpeting in the hatch maybe because i have none there. Anyway im not sure what this does other then you can tune it but if i got this:
http://www.andysautosport.com/mazda/...x00144711.html and an aem wideband or does this count as a wideband too? Would it help me out a lot performance wise? After i got a tune w it i guess