Installing RP O2 Sensor
 

(didn't find much with a search)

I just bought a new O2 Sensor from RP (Rotary Performance). Their web site says:

"the only main difference is that the Mazda unit has the plug to attach to the engine harness where as on the aftermarket unit there is no plug so you simply attach the plug that came with the original O2 sensor to the new aftermarket sensor."

From looking at my existing stock one...it looks like I'm going to need to actually cut the wire and "clip" it onto the new one. Is that correct?

I removed the heat shield covering the fuel stuff and was able to some access from the top...but probably not enough to get some leverage on a wrench. Is removing the O2 sensor from the underneath the best way to go?

Thanks for any info on this procedure. :)

Yes, do it from the bottom and yes, cut the O2 line and then clip the new one onto it.

Shouldn't take more than 5-10 minutes to replace one if you work from underneath the car. ;)

Good luck!