02 gauge not reading after removal of rear 02

[95talonracer]

I was told before that all you need to do is remove the stock rear 02 sensor because it just tells if your cat works or not. I am running a safc with a wideband to tune. all i did is unplug the rear 02 and left it alone. Do i have to do something to the rear instead of just removing it or not. It runs fine without it it seems but my usless narrow band sais its lean all of the time. the wideband also reads fine like it is supposed to at 14.7 around on normal driving and what should i tune it to under WOT. under idle the wideband reads low 16's. is that bad. Shoulf i just take off the downpipe and weld in a new bung closer to the turbo for the wideband and put the rear 02 back in? thanks!!