Eric,
The aluminum pieces are mounted using the same bolts that hold the cable guides. See pic. Really simple actually, just grab a piece of aluminum from Lowes, cut to length, drill holes, and presto. However, The 1/8" aluminum I used is actually a little weak...they aren't falling off or anything, but the gauge cluster does shake a bit when you go over rough ground. I'd use something stiffer if possible. 1/4" is probably too thick...unless you get longer bolts...maybe 1/8" steel is the way to go...but obviously a little more $.
Cutting down the windscreen didn't make much difference at all...maybe a little a certain lower speeds (30-40), but over that and the noise was still unbearable. Personally, I wouldn't recommend cutting down the screen...unless you are just doing it for appearance...other than that it's a waste of time and screen. With my current setup, the wind noise is much better....there is more wind on my chest obviously, but it doesn't bother me no where near as much as the wind that the windscreen threw in my face. Buffeting is better too....as has it's been described before, "the air is cleaner" (less turbulent). If you want to experience the difference in wind noise, just stand up on your bike at speed...that is almost exactly what it's like after the conversion....that's one thing that convinced me to do the conversion in the first place.
For turn signals, I reused the stock ones, but had to remove the rubber part and use a piece of rubber hose to shim the stem (bolt). You'll see why as soon as you take them apart. See pic.
I built my own headlight relay kit using parts I got from
www.partsexpress.com. THIS ISN'T REQUIRED, but since I went from 1 55w bulb to 2 55w bulbs, I thought it was a good idea. It works well too!
relay holder: $1.90
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=330-078
relays (x2): $5.00 (2.50 each)
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=330-079
fuse holder: $1.25
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=070-675
You'll need some 12 or 14 gauge wire and your favorite connectors, but you can get those anywhere...I had enough lying around to do the job.
headlights with brackets: $218
reuse turn signals: $0 (there is some slight modification needed..see pic)
aluminum: $5-10
headlight relay kit: ~$15 (OPTIONAL)
I think that's it...beyond that, just a little time.
hope that helps...let me know if you need more info.