I have that same gauge on my crx with a b16 and I use it as my only o2. the red is 12v switched, black is ground ( which you already have) the white is the 0-5 v output ( or you can select the output on the back of the gauge to read a lower range I.E. 0-2v or 0-1v) if your ecu reads the stock o2 as 0-5v then leave the adjusment to p0 ( as it was out of the box) if the ecu reads smaller the adjust to an apropriate range, I have hondata so the 0-5v worked for me.

once you have that, the white wire is connected to your ecu o2 sensor SIGNAL input wire ( not sure what the color code is on yours but someone else mabe able to shed some light) and just unpluging your stock o2 will prevent the stock wire from getting a signal, so you don't have to cut the wire you can solder or splice onto it. for the o2 sensor heater cel that your asking about, take a 1k ohm 1/8 watt ( at least 1/4 watt prefered)resistor (radioshack extreemly cheap) and either at the ecu or at the o2 plug connect the resistor to the 2 wires that go to the heater control ( one power and one ground). the resistor will let the ecu see a load and fool it to think the heater is good. This worked perfect in my car until I found out where to turn it off in the hondata editor.

the blue wire is not used.

also if you have problems with the car hesitating at a constant rpm and find you have to increase rpms to stop it or turn off the car and then back on again, its the wideband, you will need to have your rom reflashed to run in open loop mode. I had this problem and no one at aem had a clue, but I noticed while tuning it didn't have this problem, so I have been running in open loop for over a month and no problems.

pm if you need anymore help.