It's also not that hard to do after the plane is fully assembled, as long as you run the wiring while you are building.
When I got ready to install my Duckworks HID's, I realized that my wing cradle would put the load right where the lights go. So my lights sat on the shelf for over 2 years. In the mean time, Duckworks came out with a better, lower cost light then the one's I had purchased. No telling what will be available in a couple of years.