Nice tuck/clean-up!
I did one on my S13 track car, but am having to go back and re-do everything to try to get the car legal. The single biggest wiring saver is those damned pop-up lights. If you go Silvia front or another fixed light, you can save a ton. A/C is another huge one, but some people can't do without it.
+1 on the coolant reservoir mounting. I mounted mine as pictured below and never had a single problem.
Mine isn't as bling as yours though, but you can't beat a $20 part.
