In September 2003, I decided to take my quest of adding lightness to the next level. My goals for my new project would be:

1) remove as many of the unused wires as I could (AC, radio, cruise, airbag, etc) from under the hood/dash
2) remove the heater fan, heater core, control panel, and duct work
3) remove the starter switch and replace with toggle switch and Big Red Button (totally keyless ignition)
4) build a panel in place of the radio surround for a boost gauge, air/fuel gauge, radiator fan switch, link ecu keypad, etc
5) remove any other weight I can find under the dash (firewall insulation, grind down extra studs or brackets, etc)
6) possibly move the ecu under the dash vs under the carpet (getting rid of "heavy" metal cover)
7) move my diagnostic connector, relays, and fuses from under the hood and into the cabin (hopefully to the pax side of car)
8) insure that ZERO wires are going through the driver's side firewall
9) cross my fingers and get the car running again

Six months later I had completed the project. It cost me about $40 for new switches, fuses, and relays but I sold my radio surround, ignition switch, and a few other things so I probably came out ahead as far as money. The six months of tracing down EVERY SINGLE WIRE in the entire Miata was very educational and an experience that I will never forget. In retrospect, I probably should have just built a new wiring harness instead of unwrapping mine and pulling wires.

Here are the "official" weights of the stuff removed:
Heater fan and hoses - 4.5#
Heater core and box - 7#
Heater control panel - #1.25
Wires removed (includes brackets, tape, connectors, etc) - #15.25
Firewall insulation - 5.25#
Ignition switch - 1.75#
Air ducting (behind dash) - 1.5#
Combo switch and clock spring - 1.25#

What it looks like under the dash:

Large bundles of wires by the steering wheel:

The wires after the wrap has been taken off:

Note how many wires are laying across the transmission tunnel:

About half of the bundle has been removed:

Wiring for the underhood fuse box:

Wiring for the ECU:

Just about completed:

Still a big mess by the underhood fuse box:

Harness for the AFM. 8 feet of this will be removed:

Stock harness coming through the driver's side firewall (entire bundle will be moved/removed):

Stock driver's footwell fusebox (this will be removed and I will install my own fuses):

What a nightmare! I wanted to give up at this point:

Very messy but note only 10 wires or so are left on the transmission tunnel:

Getting ready to move the fuses to the passenger's footwell:

A few snips later and this is what I was left with. Time to get the wire crimpers:

Driver's side firewall bundle is GONE!

The combo switch (turn signals, blinkers, lights, etc) is removed:

The heavy ignition swith is also removed:

Getting closer:

The dashboard harness is removed and the dash brace is disassembled:

The metal dash brace is installed to judge where the new control panel (starter switch, turn signals, etc) will be placed:

Looking at the wiring diagram for starter switch, lights, etc:

At this point I am completely clueless on how to continue. The pushbutton starter (BRB) is very confusing for me:

Two weeks later and I can start the car (BRB, starter switch, main starter relay):

Prototype control panel made from cardboard:

Look how clean the passenger side firewall came out:

My wife's Miata for comparison:

The driver's side firewall is completely bare:

Underdash wires are bundled up with wire loom (note the fusebox in the upper right corner):

Wires are bundled together:

Even after the wire loom is added this is still a confusing mess:

Getting ready to make my control panel:

Control panel (made from an old clipboard) is installed. Left to right (starting at the top):
Accessories (intercooler water pump, etc)
Air/Fuel Mixture
Starter button (yes, it is a 1-player arcade button)
Ignition switch
Horn (2-player arcade button)
Turn signals
Running lights

Over 15 pounds of wires. Note the size of the fusebox at the top left corner. This pile is huge!

16 pounds of junk that is no longer under my dash!