I just went through this process with a 2002 DRZ400E dirt model. I put a brake switch on with an Acerbis LED talilight, attached a hi/low beam switch hooked up to the stock headlight. On 2002 and later DRZ's they come stock with a 2 way bulb - just look for the 3rd wire and that is low beam. I bought a 12v horn (sold through bicycle shops), and a fold down mirror.

I also put on DOT knobbies (Dunlop 606 in rear and Pirelli on the front - note all Pirelli knobbies are now DOT legal)

I did not have the high beam indicator. I got the green sheet TJ's, who did the inspection, and took it to the TDOT office for my plate with no problems.

The only thing I learned is this was a used bike I bought and since I was licensing it for the street I had to pay sale tax! If I was smart, I would have transferred the title while it was still a dirt bike and then changed it to a street legal bike with the title already under my name.