Got one of these, and stuck it on my car the other week. Question though. There's a tapped T coming off the side, looks like an O2 sensor for a 3rd sensor.

Why is that there? I would think if you're going to read exhaust gasses, you'd want it precat for the most accurate reading. It's only a cat back exhaust system, so I plugged the hole. (No F/A gauge here)

 

I think is was for the Evo VIII cause your o2 sensor is in your cat. The VIII is in the cat back section.

 

Ahhh that makes sense. Well damn them for not updating the cat back section! Oh well, I guess since the brackets and parts all lined up, I shouldn't compain :P Thanks for you info!