This looks like a great build! I too have an FD1 and am a SAR volunteer, so I'll keep a close eye on what kind of awesome things you do to this thing. You should check out Husky Liner formed floor mats and cargo liners. The front, rear, and cargo liners come to about $405USD but let me tell you, they are so worth while. They keep the floors and lower trim pristine especially with how much muck tends to be brought in after 12 hours through the bush. I don't have them in my Patriot yet but they were in my Mazda3 for years. The dealership which bought was amazed at how clean the floors and trim were because of them.
I'm planning to build a low profile cage along the sides of the trunk for recovery gear and possibly even a system for a backboard. If it works out I'll post some photos.
Ever had any experience with WeatherTech mats? If so, how are they compared to HuskyLiners?