That's an impressive pile of non-OEM crap! Removing it will require a lot of careful, meticulous work. Fortunately
it looks like most of the alarm wiring is a different gauge than the car's making it easier to identify. I'm guessing
that the factory wiring bundles that have been retaped are where the splices are. I'd remove the tape, find the
splices, and retape above and below them so other bundle is kept together while you work. Find both ends of
each cut wire and figure out how you're going to resplice them before cutting anything so you have a reasonable
belief things will be back to original before you start. And try to identify the purpose of each cut wire through the
wiring manual so you know if things make sense.
The one I'd be extra wary of is the fat yellow wire heading into the ECM - it's purpose may be to prevent the
car from running.
Good luck!

 

With the help of this showing all of the fuses/relays for the Honda S2000, I found I had 3 blown fuses underneath the steering column area.

Replacing them allowed me to:

1. Open the trunk using the switch in the center console.
2. Pair two Key FOBs to the car. But now when I try to unlock the car all I hear is a clicking sound. But none of my doors actually unlock/lock still. Maybe actuators are dead?
3. Have working interior lights, taillights, license plates lights etc. The car recently stopped having all the lights (except the Headlights) work.

 

Thanks for your comment. I ended up having the entire loom of aftermarket harness mess removed and now all my wires are re-soldered to the factory connector. I now have unlock/lock working on my key fob.