I haven't posted here in a while, so I figured I should contribute to the community and give my experiences with my installation of oznium.com cathodes and LEDs on a gen 4.5 2000 Toyota Camry.
Mod took me about 3 hours total outside on the car, with about 2 hours of planning and wiring before I stepped in. Keep in mind this is the first time I ever wired anything (besides a metal halide aquarium retrofit)
I used a: (everything bought from oznium except fuse)
1 x Scion tC OEM style switch , which turned out to be a perfect fit for the slots next to steering wheel
2 x 12" Cold Cathode tubes blue, with two transformers
2 x 9.5" LED strips, blue
1 x mini add-a-circuit for source of power
What I did:
I calculated the draw and fuse size I would require for this, keeping in mind that fuse size should equal 1.5 times or so the total draw of all the lights (in this case, a 3 amp fuse was as close as I could get). Also, I chose 18 gauge wire because it was more than sufficient for my load. (Max of 4.6 amps I think?)
I hooked up all my wires to the switch for preparation
I hooked up the mini add-a-circuit to an existing fuse inside my fuse box under the steering wheel and put in the switch.
I then removed some of the carpet from both sides of the center console, and using a bent hanger, threaded the necessary wires through

this isjust an example. I also had the cold cathode transformer wires sticking out
I mounted the cold cathodes and leds, and hooked everything up together via butt connectors, wirecaps, electrical tape, and zip ties
I also connected all of the grounds to a single wire attached to a ground (A metal bolt that I found attached to the chassis of the vehicle) that was conveniently found beneath the steering wheel
. Here's the results. I hope you enjoy!

Footwells

Under the seats

Everything on, including my dome light, which is a 16 blue led light.