Well, they make for really well mounted frame sliders!
I tried a new method last night to install some frame sliders. I used a laser pointer to line everything up.
Basically, you put the laser pointer on a stand so that you can line it up with the bolt holes exactly. On the F4i at least, the place where you mount the frame sliders is hollow if you take both bolts out. When they are both out, you know you are lined up because the laser will shine right though the bike.
Once you have the laser all lined up, put the fairing on. You'll have a nice, bright dot right where you should drill. Take the fairing off and repeat on the other side.
I did this and drilled my 2" frame slider holes with a 2" hole saw. They both friction fit into the fairing with no gap around the silder at all.
A quick pic of how accurate you can get the alignment: