Does anyone have this downpipe or know what it is like?

Also, do i need to get the second bung for an o2 sensor? will that help not cause a CEL or is it just useless?

 

a second bung is usually so that you can add a second o2 sensor, like for a wideband.

 

We Have quite a few of these Downpipes running around locally.
Everyone likes them, we use the best parts money can buy on them.
In terms of a second Bung that is for a wideband if you have one.
In terms of Cel issues you shouldn't get one with our Downpipe.