Having looked at your pics in your garage, you'd be mad to sell!!. Such a lovely machine. I've read that your have a welded diff, having been in a car with one fitted ( a drift s13), I thought it was horrid, no doubt it's putting undue pressure on your G/box components whenever you're cornering, and the weakest link is the clutch, so I reckon you're right in that it's the source of the clutch wearing issue.
As for the fire, electrics seem like a dauting issue, but when you get stuck in, there's not really much to it. Get a section of the loom you need from Keron and splice it in. Continuity check all your wiring afterwards and go from there.
You've obviously put a massive amount of work into it, I promise you'll regret it.