I am, quite literally, the world's WORST electrician and even I was able to do this without any problems.
When I decided to do this conversion, the one thing I kept saying was that I wanted to keep everything as stock as possible so I could put the fairing back on easily (should I want it during colder weather or when I went to sell). However, I quickly realized that wiring the headlight into the bike would be so much easier if I just cut the connectors on the headlight and stock harness off.
I had used a beauty of a little electrical connector called a Posi-Tap when I installed the Hyperlights on the rear end of the bike, so I knew the easiest way to connect the headlight wiring to the stock harness was to use another product of theirs called the Posi-Lock. Where the Posi-Tap connectors allow you to tap into a wire without cutting it, the Posi-Lock connectors allow you to simply thread a stripped wire into each end of the connector, screw down a little cap, and you've got a great, tight connection.
I cut the stock connector off the headlight. There are 4 wires coming through it...(1) left headlight, (2) right headlight, (3) 1 ground wire that runs to both headlights, (4) and the wire that powers the small parking light that sits in the housing between the main headlights.
I then cut both headlight connectors off the stock harness. This will leave you with another 4 wires, although not all grouped together like on the Buell headlight. 2 come out at one point, and 2 come out further down on the harness (the headlights are further apart on the stock FZ6 headlight). On the stock harness, you'll have (1) left headlight hot wire, (2) left headlight ground wire, (3) right headlight hot wire, (4) right headlight ground wire.
I then maneuvered the stock harness so I could twist the 2 ground wires from the bike side together (as stated above, you've got 2 ground wires on the bike side but only 1 on the Buell headlight side). After that, you simply match up the right headlight wire from the headlight to right headlight wire from the stock harness and left to left. Connect them with a Posi-Lock. Do the same with the ground wires...1 ground wire from the headlight into one end of a Posi-Lock and 2 ground wires (twisted together) from the stock harness into the other end.
As far as the little running light in the middle of the headlight goes, I used some extra wire to extend it so I could run it up to the left turn signal running light wire. I cut the running light wire, twisted the two pieces of that wire together and inserted them into the end of a Posi-Lock connector. I then inserted the extended wire from the headlight into the other end.
It's a pretty clean install and the Posi-Locks are extremely durable. Check out Web Bike World's review of all the Posi products. I've been very impressed with how well they perform and how durable they are. BTW, I picked up a sample set of the Posi-Locks (3 different sizes, 4 or 5 of each size) from Car Quest.
Posi-Lock - Posi-Twist Connectors - webBikeWorld
I know that's a lot of information and it seems confusing, but once you get the fairing off and are able to get a look at the stock harness and the headlight side-by-side, it becomes clear that it's a really easy connection to make.
, but let's be real, you can't really see **** in them!!! I mean I can see whether there's a car behind me or not (all I need them for), but gauging the distance is hard, and everything looks tiny in them!! And you have to take your eyes wayyyy off the road to look at them... I am not saying they don't work, I just think stock mirrors in general (except on the Ducati 848 or 1198 lol) provide much better rear visibility... 
