Every state has its own laws about what is required to make a motorcycle street legal. In New York, you need a High beam and low beam headlight, turn signals, tail/brake light, horn, and one mirror.
I own the XC-W which has a headlight, taillight, and a limited fuse block, so the bike had to be rewired to make
it street legal. The first thing to address is how to distribute power. The Fuzeblocks FZ-1 distribution bock is small and allowed me to wire accessories as always powered or only powered when the bike is running. This is a great feature; the only thing I can turn on when the bike is not running is the headlight. For easy access, I mounted it under my dashboard. ( check out My Custom Dashboard)
After I found a way to distribute power, I needed to watch my power consumption since the 500 only produces 90 watts. I went all LEDs for the lights to conserve energy for the heated grips ( check out creature comforts and sparkle). For the turn signals, I used Superbrightleds weatherproof LED light strips in amber and installed them on the barkbusters. They are easy to replace, and if you bust a couple of bulbs they still work, unlike the stalk signals, which stick out and always get knocked off. For the rear, I used tusk mini flush mount LEDs,
Next, the taillight and headlight both come with the bike, but the taillight 
needs to be connected to a Baja Designs hydraulic brake switch for Brembo Brakes to operate off the rear brake. I also installed a flashing chase weatherproof led stip to increase my visibility beyond the weak stock taillight. Both the headlight and taillight wiring were removed from the stock fuse block and rewired to the Fuzeblock.
For the horn, I used the Hella motorcycle series and placed them under my auxiliary lights mounted on the forks and for the mirrors, I went with the Double Take Endro Mirrors.
