Installed some new creature comforts.
8" sub hidden in some dead space in the rear:
Infinity Kappa speakers all around. These are a lot more efficient, so I was able to delete my amplifier.
Honda CR-Z seats:
Ever wonder what the inside of a seat looks like? I pulled them apart for cleaning and removed the airbags and what appeared to be a controller for heating the passenger seat. They were still probably twice as heavy as the Insight's seats.
The new seats weren't quite drop-in replacements, and required that I make adapters.