is it better to go off the ECU or the O2 sensor?

also i have a auto meter gauge, and there is 3 wires. i am guessing red is batt + black batt - and the purple is for the O2. just wanted to make sure
thanx

 

you are correct on wire colors, you will want to hook it up as close to the O2 sensor as possible that way you get a better reading. something happens when hooked to the ecu i forgot what but its bad juju dont want to do it

 

yeah thats the colors mine is
thank you for the help. yeah i heard bad things about hooking up to the ECU also. but just wanted to make sure.

what colors are should they to be?

i have red/black/purple
its a atuo meter street comp. [silver faced]

 

no you have the right colors i have the same on mine (phantom) i have mine hooked up about 4 inches away from the O2 sensor i wish i woulda put it closer but oh well