When you say shims are you referring to the slider plates?:
Alot of people bin them as they can cause the pads to seize into the carriers, but IME, given the right car they are fine and get rid of clunks and rattles as well as giving a freer surface for the pad to glide on (after all, they are smooth...)
Most brake pads don't come with the shims/sliders for the pads to slide on unless you go for Renault parts.
If it were me I would:
-Buy some sliders
-Take a wire brush on a drill to the slider plate (shims) mating faces and clean them thoroughly;mine had some surface rust present and caused the pads to bind, especially the inner pads, sandpaper and your finger will have you doing it for a very long time.
-Grease the mating surfaces, unless you fancy repeating the above in the not so distant future
-Grease the slider plates where the pad ears sit (I'd use ceramic grease only for this application and for beneath the plates as well).
-Reassemble.
For me (albeit on stock pads) this worked and even after a trackday at Cadwell the pads never binded. A year later the pads still went across the plates very freely, moreso if that if nothing was there IMO.
If you mean another kind of shim, disregard the post
.