I have no experience with an SAFC, so no help with that. As far as the wideband, that really depends on which one you get. For the most part, you will install the sensor in your exhaust, run that to the computer/chip/whatever calculates your air/fuel ratio/ and then there will be an output to a some kind of monitering device (like a gauge). You may also be able to log the output (I log mine via DSMLink).

As far as gauges, that depends on whether you have electronic or mechanical gauges. To start, after I installed all of my gauges, I ran a wire from a 12v signal from where the mirror adjusters are. I did this as now, they will only turn on (the light that is) when you at least turn the parking lights on. Now, obviously your boost gauge will be mechanical, so you just run a vacuum hose from a boost source to the back of the gauge. You would do the same for any other mechanical gauge. For electronic gauges, you install the sender in the engine bay, and then run a wire to the back of the gauge. You also need to run a wire from the gauge to the ignition wire so they only are on when the car is on. I hope this helps. If not, VFAQ has some pretty good instruction on how to wire them up and what not.

As far as actually running things into the car throught the firewall, I went through the top of the steering column boot.

'95 GSX - New motor/turbo going in...
'95 TSi AWD - For sale...buy me!
'03.5 MazdaSpeed Protege - Stock daily driver
'97 CBR 600 - Purple is a real man's color