Hey guys, i also own a Mazda 6s v6, and i just bought some MSDS shorty headers that i'm going to install, and do a custom true dual for it. So far it is going to be the only true dual exhaust in the Mazda community. The question i have is this:

-the stock car has an o2 sensor right after the headers on the y-pipe.
-but now that i am installing true duals, their are going to be two pipes and only one o2 sensor. So what i'm planning on doing is installing a magnaflow x pipe where the y pipe used to be, and tap the middle of the xpipe and install the o2 sensor there. Would that be ok? Any other ideas would be great.

 

I think tapping the x-pipe would be fine. You could also just tap bank 1 or bank 2 of your true-dual to install the downstream 02 sensor, and that should work okay too.

 

so any other input?