Went ahead and installed the ST43s today to wear in at the 4/15, 4/22, 4/29, and 5/27 autox events in the Evo. I had leftover titanium shims (!) from Girodisc that I added with them. These are from the soft-brake fiasco in 2016. The shims didn’t sit flush with the back of the S/S brake pad due to a wear-bump on the back of those pads. These pads have the wear-bump, but it does not protrude over the back of the pad, and the shims sit flush. So, I wound up with two sets of titanium shims, one for the S/S pads & one for the ST43s. The latter is probably more crucial since those will be used on the track.
Also worth noting, the ST43s have a slot in the middle of the pad, whereas the S/S pads do not. They are also not chamfered, where the S/S pads are. There are a number of advantages to slotted pads – it can serve as a wear indicator, reduce stiffness/prevent cracking, clean the rotor, and dissipate heat. They can also decrease noise, though I doubt that will be the case here.
Continuing to follow my minimal anti-seize regimen, with antiseize between the pad & the shim, but none between the shims & the pistons, to let the vented pistons have clear breathing. Also took the time to clean the rear calipers, the pistons, remove the rear pads, use sandpaper to gently clean the shims and reassemble & reinstall all. Hopefully the rears will be able to perform a little better also, with the vented pistons now clear with no antiseize in the rear as well.
Old shim, sitting flush with the back of the pad
vs. the S/S set up – bump protrudes, so Girodisc sent cut ti shims: