It's called google.
Your not going to be able to just hook an O2 sensor to led's and expect it to work.
http://lmgtfy.com/?q...uel monitor kit
http://lmgtfy.com/?q...e wiring basics
Its that easy. Google is your friend
Yeah I have been looking around at how other cars have setup theirs I just didnt know if any of the older model subarus on here had done stand alone fuse boxes. And yes I have searched the site for "stand alone fuse box". Nothing of value came up.
You will want to install a relay for each component as to not overdraw a switch or have heavy gauge wire come thru the cabin. If you are good, you can wire the driving lights to come on with the low or high beam using the headlight circuits to trip the relays. I have done this with a pair of driving lights to come on withthe high beam, tapping into a headlight socket, as the headlights are hot all the time, and ground thru the switch. The relay would be connected as a 'positive ground', and the driving lights connected to the battery normally. You will want a basic understanding of wiring schematics. Otherise, wire the relay to a toggle switch, and wire the driving lights to the to the relay.
For the wideband monitor, you will want to tie into the interior lamps to light up, unless you wire it up with the key.
Yeah relays have come up a lot as I have been reading around. I would just want to set it up completely manual with a toggle switch on the headliner. O2 sensor I will try to wire separate as well, I want to try to prevent splicing directly into other wires. Getting them to come on with high beam does seem like a really convenient idea though.