Those complicated add-on screens can work, but you need a lot of experimentation to get them adjusted just right and they can get pretty pricy. And then there is the issue of how hard it is to clean bugs off of those various surfaces. 
You know how bugs are. They always go to die on the shield edges and supports. 
Richard, Richard, you know there's no bugs in San Francisco's cold climate!
I've got some kind of spray-on bug remover from Kragen's that works. Just let it set a couple of minutes and hit with with the hose nozzle stream. Bye bye bugs. Besides, I only wash my bikes every 6 months whether they need it or not.
Adjustment? It's a breeze! Pun intended. I've got it fine tuned and make it just what I want for any day's condition in about 5 seconds: Unlock the cams with gloved hands. ( flip flip) Push the moveable screen down or pull it up. Leave the spoiler all the way up. Push the cams back down in place (flip flip) Done. On the freeway, at, um, exactly 65.0 mph officer.
And cost? Heck, you own BMW's! Need I say more?
All seriousness aside, the Givi and the Vario didn't break the bank. Way way less than a Parabellum Scout. It was GETTING to that solution with all the other windscreens I didn't like (ZTechnik version 1 was AWFUL!) that drained my bank account!
- Bill
