My 2006 S40 has no shims on the brake pads. When I looked up the parts needed for me to replace the brake hose, and rebuild the master cylinder and caliper, I saw that the drawing shows two shims for the brake pas. Since my bike was used I was not sure if someone lost them or if they just are not needed. I also saw the post from someone here on replacing the pads and there was no mention of a shim. The shim is number 15 on bike bandit website. Please let me know if you guys have shims or not and if they are really needed. thanks, S40 Guy.
http://www.bikebandit.com/2006-suzuki-boulevard-s40-ls650/o/m147605#sch510383

I use the bright red anti-squeal lube on the back (piston) side of the pad. just a dab(a finger tip full), and don't get any on the pads or rotors. I bought a bottle of that back in the '90s and it's still more than half full.

No squealing, and it increases the life of the pads by reducing the resonance  between the rotor and the piston - it allows the pad to move a bit against the piston while braking.